Add m-esr52 at 52.6.0

41 files changed, 6784 insertions, 0 deletions

diff --git a/dom/media/systemservices/CamerasChild.cpp b/dom/media/systemservices/CamerasChild.cpp
new file mode 100644
index 0000000000..0f7d1c1dfd
--- /dev/null
+++ b/dom/media/systemservices/CamerasChild.cpp
@@ -0,0 +1,724 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CamerasChild.h"
+
+#include "webrtc/video_engine/include/vie_capture.h"
+#undef FF
+
+#include "mozilla/Assertions.h"
+#include "mozilla/ipc/BackgroundChild.h"
+#include "mozilla/ipc/PBackgroundChild.h"
+#include "mozilla/Logging.h"
+#include "mozilla/SyncRunnable.h"
+#include "mozilla/WeakPtr.h"
+#include "mozilla/Unused.h"
+#include "MediaUtils.h"
+#include "nsThreadUtils.h"
+
+#undef LOG
+#undef LOG_ENABLED
+mozilla::LazyLogModule gCamerasChildLog("CamerasChild");
+#define LOG(args) MOZ_LOG(gCamerasChildLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gCamerasChildLog, mozilla::LogLevel::Debug)
+
+#define FAKE_ONDEVICECHANGE_EVENT_PERIOD_IN_MS 5000
+#define FAKE_ONDEVICECHANGE_EVENT_REPEAT_COUNT 30
+
+namespace mozilla {
+namespace camera {
+
+CamerasSingleton::CamerasSingleton()
+  : mCamerasMutex("CamerasSingleton::mCamerasMutex"),
+    mCameras(nullptr),
+    mCamerasChildThread(nullptr),
+    mFakeDeviceChangeEventThread(nullptr) {
+  LOG(("CamerasSingleton: %p", this));
+}
+
+CamerasSingleton::~CamerasSingleton() {
+  LOG(("~CamerasSingleton: %p", this));
+}
+
+class FakeOnDeviceChangeEventRunnable : public Runnable
+{
+public:
+  explicit FakeOnDeviceChangeEventRunnable(uint8_t counter)
+    : mCounter(counter) {}
+
+  NS_IMETHOD Run() override
+  {
+    OffTheBooksMutexAutoLock lock(CamerasSingleton::Mutex());
+
+    CamerasChild* child = CamerasSingleton::Child();
+    if (child) {
+      child->OnDeviceChange();
+
+      if (mCounter++ < FAKE_ONDEVICECHANGE_EVENT_REPEAT_COUNT) {
+        RefPtr<FakeOnDeviceChangeEventRunnable> evt = new FakeOnDeviceChangeEventRunnable(mCounter);
+        CamerasSingleton::FakeDeviceChangeEventThread()->DelayedDispatch(evt.forget(),
+          FAKE_ONDEVICECHANGE_EVENT_PERIOD_IN_MS);
+      }
+    }
+
+    return NS_OK;
+  }
+
+private:
+  uint8_t mCounter;
+};
+
+class InitializeIPCThread : public Runnable
+{
+public:
+  InitializeIPCThread()
+    : mCamerasChild(nullptr) {}
+
+  NS_IMETHOD Run() override {
+    // Try to get the PBackground handle
+    ipc::PBackgroundChild* existingBackgroundChild =
+      ipc::BackgroundChild::GetForCurrentThread();
+    // If it's not spun up yet, block until it is, and retry
+    if (!existingBackgroundChild) {
+      LOG(("No existingBackgroundChild"));
+      existingBackgroundChild =
+        ipc::BackgroundChild::SynchronouslyCreateForCurrentThread();
+      LOG(("BackgroundChild: %p", existingBackgroundChild));
+      if (!existingBackgroundChild) {
+        return NS_ERROR_FAILURE;
+      }
+    }
+
+    // Create CamerasChild
+    // We will be returning the resulting pointer (synchronously) to our caller.
+    mCamerasChild =
+      static_cast<mozilla::camera::CamerasChild*>(existingBackgroundChild->SendPCamerasConstructor());
+
+    return NS_OK;
+  }
+
+  CamerasChild* GetCamerasChild() {
+    return mCamerasChild;
+  }
+
+private:
+  CamerasChild* mCamerasChild;
+};
+
+CamerasChild*
+GetCamerasChild() {
+  CamerasSingleton::Mutex().AssertCurrentThreadOwns();
+  if (!CamerasSingleton::Child()) {
+    MOZ_ASSERT(!NS_IsMainThread(), "Should not be on the main Thread");
+    MOZ_ASSERT(!CamerasSingleton::Thread());
+    LOG(("No sCameras, setting up IPC Thread"));
+    nsresult rv = NS_NewNamedThread("Cameras IPC",
+                                    getter_AddRefs(CamerasSingleton::Thread()));
+    if (NS_FAILED(rv)) {
+      LOG(("Error launching IPC Thread"));
+      return nullptr;
+    }
+
+    // At this point we are in the MediaManager thread, and the thread we are
+    // dispatching to is the specific Cameras IPC thread that was just made
+    // above, so now we will fire off a runnable to run
+    // BackgroundChild::SynchronouslyCreateForCurrentThread there, while we
+    // block in this thread.
+    // We block until the following happens in the Cameras IPC thread:
+    // 1) Creation of PBackground finishes
+    // 2) Creation of PCameras finishes by sending a message to the parent
+    RefPtr<InitializeIPCThread> runnable = new InitializeIPCThread();
+    RefPtr<SyncRunnable> sr = new SyncRunnable(runnable);
+    sr->DispatchToThread(CamerasSingleton::Thread());
+    CamerasSingleton::Child() = runnable->GetCamerasChild();
+  }
+  if (!CamerasSingleton::Child()) {
+    LOG(("Failed to set up CamerasChild, are we in shutdown?"));
+  }
+  return CamerasSingleton::Child();
+}
+
+CamerasChild*
+GetCamerasChildIfExists() {
+  OffTheBooksMutexAutoLock lock(CamerasSingleton::Mutex());
+  return CamerasSingleton::Child();
+}
+
+int CamerasChild::AddDeviceChangeCallback(DeviceChangeCallback* aCallback)
+{
+  // According to the spec, if the script sets
+  // navigator.mediaDevices.ondevicechange and the permission state is
+  // "always granted", the User Agent MUST fires a devicechange event when
+  // a new media input device is made available, even the script never
+  // call getusermedia or enumerateDevices.
+
+  // In order to detect the event, we need to init the camera engine.
+  // Currently EnsureInitialized(aCapEngine) is only called when one of
+  // CamerasaParent api, e.g., RecvNumberOfCaptureDevices(), is called.
+
+  // So here we setup camera engine via EnsureInitialized(aCapEngine)
+
+  EnsureInitialized(CameraEngine);
+  return DeviceChangeCallback::AddDeviceChangeCallback(aCallback);
+}
+
+bool
+CamerasChild::RecvReplyFailure(void)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = false;
+  monitor.Notify();
+  return true;
+}
+
+bool
+CamerasChild::RecvReplySuccess(void)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  monitor.Notify();
+  return true;
+}
+
+bool
+CamerasChild::RecvReplyNumberOfCapabilities(const int& numdev)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  mReplyInteger = numdev;
+  monitor.Notify();
+  return true;
+}
+
+// Helper function to dispatch calls to the IPC Thread and
+// CamerasChild object. Takes the needed locks and dispatches.
+// Takes a "failed" value and a reference to the output variable
+// as parameters, will return the right one depending on whether
+// dispatching succeeded.
+template <class T = int>
+class LockAndDispatch
+{
+public:
+  LockAndDispatch(CamerasChild* aCamerasChild,
+                  const char* aRequestingFunc,
+                  nsIRunnable *aRunnable,
+                  const T& aFailureValue = T(-1), const T& aSuccessValue = T(0))
+    : mCamerasChild(aCamerasChild), mRequestingFunc(aRequestingFunc),
+      mRunnable(aRunnable),
+      mReplyLock(aCamerasChild->mReplyMonitor),
+      mRequestLock(aCamerasChild->mRequestMutex),
+      mSuccess(true),
+      mFailureValue(aFailureValue), mSuccessValue(aSuccessValue)
+  {
+    Dispatch();
+  }
+
+  const T& ReturnValue() const {
+    if (mSuccess) {
+      return mSuccessValue;
+    } else {
+      return mFailureValue;
+    }
+  }
+
+  const bool& Success() const {
+    return mSuccess;
+  }
+
+private:
+  void Dispatch() {
+    if (!mCamerasChild->DispatchToParent(mRunnable, mReplyLock)) {
+      LOG(("Cameras dispatch for IPC failed in %s", mRequestingFunc));
+      mSuccess = false;
+    }
+  }
+
+  CamerasChild* mCamerasChild;
+  const char* mRequestingFunc;
+  nsIRunnable* mRunnable;
+  // Prevent concurrent use of the reply variables by holding
+  // the mReplyMonitor. Note that this is unlocked while waiting for
+  // the reply to be filled in, necessitating the additional mRequestLock/Mutex;
+  MonitorAutoLock mReplyLock;
+  MutexAutoLock mRequestLock;
+  bool mSuccess;
+  const T& mFailureValue;
+  const T& mSuccessValue;
+};
+
+bool
+CamerasChild::DispatchToParent(nsIRunnable* aRunnable,
+                               MonitorAutoLock& aMonitor)
+{
+  CamerasSingleton::Mutex().AssertCurrentThreadOwns();
+  CamerasSingleton::Thread()->Dispatch(aRunnable, NS_DISPATCH_NORMAL);
+  // We can't see if the send worked, so we need to be able to bail
+  // out on shutdown (when it failed and we won't get a reply).
+  if (!mIPCIsAlive) {
+    return false;
+  }
+  // Guard against spurious wakeups.
+  mReceivedReply = false;
+  // Wait for a reply
+  do {
+    aMonitor.Wait();
+  } while (!mReceivedReply && mIPCIsAlive);
+  if (!mReplySuccess) {
+    return false;
+  }
+  return true;
+}
+
+int
+CamerasChild::NumberOfCapabilities(CaptureEngine aCapEngine,
+                                   const char* deviceUniqueIdUTF8)
+{
+  LOG((__PRETTY_FUNCTION__));
+  LOG(("NumberOfCapabilities for %s", deviceUniqueIdUTF8));
+  nsCString unique_id(deviceUniqueIdUTF8);
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, nsCString>
+    (this, &CamerasChild::SendNumberOfCapabilities, aCapEngine, unique_id);
+  LockAndDispatch<> dispatcher(this, __func__, runnable, 0, mReplyInteger);
+  LOG(("Capture capability count: %d", dispatcher.ReturnValue()));
+  return dispatcher.ReturnValue();
+}
+
+int
+CamerasChild::NumberOfCaptureDevices(CaptureEngine aCapEngine)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine>
+    (this, &CamerasChild::SendNumberOfCaptureDevices, aCapEngine);
+  LockAndDispatch<> dispatcher(this, __func__, runnable, 0, mReplyInteger);
+  LOG(("Capture Devices: %d", dispatcher.ReturnValue()));
+  return dispatcher.ReturnValue();
+}
+
+bool
+CamerasChild::RecvReplyNumberOfCaptureDevices(const int& numdev)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  mReplyInteger = numdev;
+  monitor.Notify();
+  return true;
+}
+
+int
+CamerasChild::EnsureInitialized(CaptureEngine aCapEngine)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine>
+    (this, &CamerasChild::SendEnsureInitialized, aCapEngine);
+  LockAndDispatch<> dispatcher(this, __func__, runnable, 0, mReplyInteger);
+  LOG(("Capture Devices: %d", dispatcher.ReturnValue()));
+  return dispatcher.ReturnValue();
+}
+
+int
+CamerasChild::GetCaptureCapability(CaptureEngine aCapEngine,
+                                   const char* unique_idUTF8,
+                                   const unsigned int capability_number,
+                                   webrtc::CaptureCapability& capability)
+{
+  LOG(("GetCaptureCapability: %s %d", unique_idUTF8, capability_number));
+  nsCString unique_id(unique_idUTF8);
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, nsCString, unsigned int>
+    (this, &CamerasChild::SendGetCaptureCapability, aCapEngine, unique_id, capability_number);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  if (dispatcher.Success()) {
+    capability = mReplyCapability;
+  }
+  return dispatcher.ReturnValue();
+}
+
+bool
+CamerasChild::RecvReplyGetCaptureCapability(const CaptureCapability& ipcCapability)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  mReplyCapability.width = ipcCapability.width();
+  mReplyCapability.height = ipcCapability.height();
+  mReplyCapability.maxFPS = ipcCapability.maxFPS();
+  mReplyCapability.expectedCaptureDelay = ipcCapability.expectedCaptureDelay();
+  mReplyCapability.rawType = static_cast<webrtc::RawVideoType>(ipcCapability.rawType());
+  mReplyCapability.codecType = static_cast<webrtc::VideoCodecType>(ipcCapability.codecType());
+  mReplyCapability.interlaced = ipcCapability.interlaced();
+  monitor.Notify();
+  return true;
+}
+
+int
+CamerasChild::GetCaptureDevice(CaptureEngine aCapEngine,
+                               unsigned int list_number, char* device_nameUTF8,
+                               const unsigned int device_nameUTF8Length,
+                               char* unique_idUTF8,
+                               const unsigned int unique_idUTF8Length,
+                               bool* scary)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, unsigned int>
+    (this, &CamerasChild::SendGetCaptureDevice, aCapEngine, list_number);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  if (dispatcher.Success()) {
+    base::strlcpy(device_nameUTF8, mReplyDeviceName.get(), device_nameUTF8Length);
+    base::strlcpy(unique_idUTF8, mReplyDeviceID.get(), unique_idUTF8Length);
+    if (scary) {
+      *scary = mReplyScary;
+    }
+    LOG(("Got %s name %s id", device_nameUTF8, unique_idUTF8));
+  }
+  return dispatcher.ReturnValue();
+}
+
+bool
+CamerasChild::RecvReplyGetCaptureDevice(const nsCString& device_name,
+                                        const nsCString& device_id,
+                                        const bool& scary)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  mReplyDeviceName = device_name;
+  mReplyDeviceID = device_id;
+  mReplyScary = scary;
+  monitor.Notify();
+  return true;
+}
+
+int
+CamerasChild::AllocateCaptureDevice(CaptureEngine aCapEngine,
+                                    const char* unique_idUTF8,
+                                    const unsigned int unique_idUTF8Length,
+                                    int& capture_id,
+                                    const nsACString& aOrigin)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCString unique_id(unique_idUTF8);
+  nsCString origin(aOrigin);
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, nsCString, nsCString>
+    (this, &CamerasChild::SendAllocateCaptureDevice, aCapEngine, unique_id, origin);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  if (dispatcher.Success()) {
+    LOG(("Capture Device allocated: %d", mReplyInteger));
+    capture_id = mReplyInteger;
+  }
+  return dispatcher.ReturnValue();
+}
+
+
+bool
+CamerasChild::RecvReplyAllocateCaptureDevice(const int& numdev)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MonitorAutoLock monitor(mReplyMonitor);
+  mReceivedReply = true;
+  mReplySuccess = true;
+  mReplyInteger = numdev;
+  monitor.Notify();
+  return true;
+}
+
+int
+CamerasChild::ReleaseCaptureDevice(CaptureEngine aCapEngine,
+                                   const int capture_id)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, int>
+    (this, &CamerasChild::SendReleaseCaptureDevice, aCapEngine, capture_id);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  return dispatcher.ReturnValue();
+}
+
+void
+CamerasChild::AddCallback(const CaptureEngine aCapEngine, const int capture_id,
+                          webrtc::ExternalRenderer* render)
+{
+  MutexAutoLock lock(mCallbackMutex);
+  CapturerElement ce;
+  ce.engine = aCapEngine;
+  ce.id = capture_id;
+  ce.callback = render;
+  mCallbacks.AppendElement(ce);
+}
+
+void
+CamerasChild::RemoveCallback(const CaptureEngine aCapEngine, const int capture_id)
+{
+  MutexAutoLock lock(mCallbackMutex);
+  for (unsigned int i = 0; i < mCallbacks.Length(); i++) {
+    CapturerElement ce = mCallbacks[i];
+    if (ce.engine == aCapEngine && ce.id == capture_id) {
+      mCallbacks.RemoveElementAt(i);
+      break;
+    }
+  }
+}
+
+int
+CamerasChild::StartCapture(CaptureEngine aCapEngine,
+                           const int capture_id,
+                           webrtc::CaptureCapability& webrtcCaps,
+                           webrtc::ExternalRenderer* cb)
+{
+  LOG((__PRETTY_FUNCTION__));
+  AddCallback(aCapEngine, capture_id, cb);
+  CaptureCapability capCap(webrtcCaps.width,
+                           webrtcCaps.height,
+                           webrtcCaps.maxFPS,
+                           webrtcCaps.expectedCaptureDelay,
+                           webrtcCaps.rawType,
+                           webrtcCaps.codecType,
+                           webrtcCaps.interlaced);
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, int, CaptureCapability>
+    (this, &CamerasChild::SendStartCapture, aCapEngine, capture_id, capCap);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  return dispatcher.ReturnValue();
+}
+
+int
+CamerasChild::StopCapture(CaptureEngine aCapEngine, const int capture_id)
+{
+  LOG((__PRETTY_FUNCTION__));
+  nsCOMPtr<nsIRunnable> runnable =
+    mozilla::NewNonOwningRunnableMethod<CaptureEngine, int>
+    (this, &CamerasChild::SendStopCapture, aCapEngine, capture_id);
+  LockAndDispatch<> dispatcher(this, __func__, runnable);
+  if (dispatcher.Success()) {
+    RemoveCallback(aCapEngine, capture_id);
+  }
+  return dispatcher.ReturnValue();
+}
+
+void
+Shutdown(void)
+{
+  OffTheBooksMutexAutoLock lock(CamerasSingleton::Mutex());
+  CamerasChild* child = CamerasSingleton::Child();
+  if (!child) {
+    // We don't want to cause everything to get fired up if we're
+    // really already shut down.
+    LOG(("Shutdown when already shut down"));
+    return;
+  }
+  child->ShutdownAll();
+}
+
+class ShutdownRunnable : public Runnable {
+public:
+  explicit
+  ShutdownRunnable(already_AddRefed<Runnable>&& aReplyEvent)
+    : mReplyEvent(aReplyEvent) {};
+
+  NS_IMETHOD Run() override {
+    LOG(("Closing BackgroundChild"));
+    ipc::BackgroundChild::CloseForCurrentThread();
+
+    NS_DispatchToMainThread(mReplyEvent.forget());
+
+    return NS_OK;
+  }
+
+private:
+  RefPtr<Runnable> mReplyEvent;
+};
+
+void
+CamerasChild::ShutdownAll()
+{
+  // Called with CamerasSingleton::Mutex() held
+  ShutdownParent();
+  ShutdownChild();
+}
+
+void
+CamerasChild::ShutdownParent()
+{
+  // Called with CamerasSingleton::Mutex() held
+  {
+    MonitorAutoLock monitor(mReplyMonitor);
+    mIPCIsAlive = false;
+    monitor.NotifyAll();
+  }
+  if (CamerasSingleton::Thread()) {
+    LOG(("Dispatching actor deletion"));
+    // Delete the parent actor.
+    // CamerasChild (this) will remain alive and is only deleted by the
+    // IPC layer when SendAllDone returns.
+    nsCOMPtr<nsIRunnable> deleteRunnable =
+      mozilla::NewNonOwningRunnableMethod(this, &CamerasChild::SendAllDone);
+    CamerasSingleton::Thread()->Dispatch(deleteRunnable, NS_DISPATCH_NORMAL);
+  } else {
+    LOG(("ShutdownParent called without PBackground thread"));
+  }
+}
+
+void
+CamerasChild::ShutdownChild()
+{
+  // Called with CamerasSingleton::Mutex() held
+  if (CamerasSingleton::Thread()) {
+    LOG(("PBackground thread exists, dispatching close"));
+    // Dispatch closing the IPC thread back to us when the
+    // BackgroundChild is closed.
+    RefPtr<ShutdownRunnable> runnable =
+      new ShutdownRunnable(NewRunnableMethod(CamerasSingleton::Thread(),
+                                             &nsIThread::Shutdown));
+    CamerasSingleton::Thread()->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
+  } else {
+    LOG(("Shutdown called without PBackground thread"));
+  }
+  LOG(("Erasing sCameras & thread refs (original thread)"));
+  CamerasSingleton::Child() = nullptr;
+  CamerasSingleton::Thread() = nullptr;
+
+  if (CamerasSingleton::FakeDeviceChangeEventThread()) {
+    RefPtr<ShutdownRunnable> runnable =
+      new ShutdownRunnable(NewRunnableMethod(CamerasSingleton::FakeDeviceChangeEventThread(),
+                                             &nsIThread::Shutdown));
+    CamerasSingleton::FakeDeviceChangeEventThread()->Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
+  }
+  CamerasSingleton::FakeDeviceChangeEventThread() = nullptr;
+}
+
+bool
+CamerasChild::RecvDeliverFrame(const CaptureEngine& capEngine,
+                               const int& capId,
+                               mozilla::ipc::Shmem&& shmem,
+                               const size_t& size,
+                               const uint32_t& time_stamp,
+                               const int64_t& ntp_time,
+                               const int64_t& render_time)
+{
+  MutexAutoLock lock(mCallbackMutex);
+  if (Callback(capEngine, capId)) {
+    unsigned char* image = shmem.get<unsigned char>();
+    Callback(capEngine, capId)->DeliverFrame(image, size,
+                                             time_stamp,
+                                             ntp_time, render_time,
+                                             nullptr);
+  } else {
+    LOG(("DeliverFrame called with dead callback"));
+  }
+  SendReleaseFrame(shmem);
+  return true;
+}
+
+bool
+CamerasChild::RecvDeviceChange()
+{
+  this->OnDeviceChange();
+  return true;
+}
+
+int
+CamerasChild::SetFakeDeviceChangeEvents()
+{
+  CamerasSingleton::Mutex().AssertCurrentThreadOwns();
+
+  if(!CamerasSingleton::FakeDeviceChangeEventThread()) {
+    nsresult rv = NS_NewNamedThread("Fake DC Event",
+                                    getter_AddRefs(CamerasSingleton::FakeDeviceChangeEventThread()));
+    if (NS_FAILED(rv)) {
+      LOG(("Error launching Fake OnDeviceChange Event Thread"));
+      return -1;
+    }
+  }
+
+  // To simulate the devicechange event in mochitest,
+  // we fire a fake devicechange event in Camera IPC thread periodically
+  RefPtr<FakeOnDeviceChangeEventRunnable> evt = new FakeOnDeviceChangeEventRunnable(0);
+  CamerasSingleton::FakeDeviceChangeEventThread()->Dispatch(evt.forget(), NS_DISPATCH_NORMAL);
+
+  return 0;
+}
+
+bool
+CamerasChild::RecvFrameSizeChange(const CaptureEngine& capEngine,
+                                  const int& capId,
+                                  const int& w, const int& h)
+{
+  LOG((__PRETTY_FUNCTION__));
+  MutexAutoLock lock(mCallbackMutex);
+  if (Callback(capEngine, capId)) {
+    Callback(capEngine, capId)->FrameSizeChange(w, h, 0);
+  } else {
+    LOG(("Frame size change with dead callback"));
+  }
+  return true;
+}
+
+void
+CamerasChild::ActorDestroy(ActorDestroyReason aWhy)
+{
+  MonitorAutoLock monitor(mReplyMonitor);
+  mIPCIsAlive = false;
+  // Hopefully prevent us from getting stuck
+  // on replies that'll never come.
+  monitor.NotifyAll();
+}
+
+CamerasChild::CamerasChild()
+  : mCallbackMutex("mozilla::cameras::CamerasChild::mCallbackMutex"),
+    mIPCIsAlive(true),
+    mRequestMutex("mozilla::cameras::CamerasChild::mRequestMutex"),
+    mReplyMonitor("mozilla::cameras::CamerasChild::mReplyMonitor")
+{
+  LOG(("CamerasChild: %p", this));
+
+  MOZ_COUNT_CTOR(CamerasChild);
+}
+
+CamerasChild::~CamerasChild()
+{
+  LOG(("~CamerasChild: %p", this));
+
+  {
+    OffTheBooksMutexAutoLock lock(CamerasSingleton::Mutex());
+    // In normal circumstances we've already shut down and the
+    // following does nothing. But on fatal IPC errors we will
+    // get destructed immediately, and should not try to reach
+    // the parent.
+    ShutdownChild();
+  }
+
+  MOZ_COUNT_DTOR(CamerasChild);
+}
+
+webrtc::ExternalRenderer* CamerasChild::Callback(CaptureEngine aCapEngine,
+                                                 int capture_id)
+{
+  for (unsigned int i = 0; i < mCallbacks.Length(); i++) {
+    CapturerElement ce = mCallbacks[i];
+    if (ce.engine == aCapEngine && ce.id == capture_id) {
+      return ce.callback;
+    }
+  }
+
+  return nullptr;
+}
+
+}
+}
diff --git a/dom/media/systemservices/CamerasChild.h b/dom/media/systemservices/CamerasChild.h
new file mode 100644
index 0000000000..1530714e98
--- /dev/null
+++ b/dom/media/systemservices/CamerasChild.h
@@ -0,0 +1,250 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_CamerasChild_h
+#define mozilla_CamerasChild_h
+
+#include "mozilla/Move.h"
+#include "mozilla/Pair.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/camera/PCamerasChild.h"
+#include "mozilla/camera/PCamerasParent.h"
+#include "mozilla/media/DeviceChangeCallback.h"
+#include "mozilla/Mutex.h"
+#include "base/singleton.h"
+#include "nsCOMPtr.h"
+
+// conflicts with #include of scoped_ptr.h
+#undef FF
+#include "webrtc/common.h"
+// Video Engine
+#include "webrtc/video_engine/include/vie_base.h"
+#include "webrtc/video_engine/include/vie_capture.h"
+#include "webrtc/video_engine/include/vie_render.h"
+
+namespace mozilla {
+
+namespace ipc {
+class BackgroundChildImpl;
+}
+
+namespace camera {
+
+struct CapturerElement {
+  CaptureEngine engine;
+  int id;
+  webrtc::ExternalRenderer* callback;
+};
+
+// Forward declaration so we can work with pointers to it.
+class CamerasChild;
+// Helper class in impl that we friend.
+template <class T> class LockAndDispatch;
+
+// We emulate the sync webrtc.org API with the help of singleton
+// CamerasSingleton, which manages a pointer to an IPC object, a thread
+// where IPC operations should run on, and a mutex.
+// The static function Cameras() will use that Singleton to set up,
+// if needed, both the thread and the associated IPC objects and return
+// a pointer to the IPC object. Users can then do IPC calls on that object
+// after dispatching them to aforementioned thread.
+
+// 2 Threads are involved in this code:
+// - the MediaManager thread, which will call the (static, sync API) functions
+//   through MediaEngineRemoteVideoSource
+// - the Cameras IPC thread, which will be doing our IPC to the parent process
+//   via PBackground
+
+// Our main complication is that we emulate a sync API while (having to do)
+// async messaging. We dispatch the messages to another thread to send them
+// async and hold a Monitor to wait for the result to be asynchronously received
+// again. The requirement for async messaging originates on the parent side:
+// it's not reasonable to block all PBackground IPC there while waiting for
+// something like device enumeration to complete.
+
+class CamerasSingleton {
+public:
+  CamerasSingleton();
+  ~CamerasSingleton();
+
+  static OffTheBooksMutex& Mutex() {
+    return gTheInstance.get()->mCamerasMutex;
+  }
+
+  static CamerasChild*& Child() {
+    Mutex().AssertCurrentThreadOwns();
+    return gTheInstance.get()->mCameras;
+  }
+
+  static nsCOMPtr<nsIThread>& Thread() {
+    Mutex().AssertCurrentThreadOwns();
+    return gTheInstance.get()->mCamerasChildThread;
+  }
+
+  static nsCOMPtr<nsIThread>& FakeDeviceChangeEventThread() {
+    Mutex().AssertCurrentThreadOwns();
+    return gTheInstance.get()->mFakeDeviceChangeEventThread;
+  }
+
+private:
+  static Singleton<CamerasSingleton> gTheInstance;
+
+  // Reinitializing CamerasChild will change the pointers below.
+  // We don't want this to happen in the middle of preparing IPC.
+  // We will be alive on destruction, so this needs to be off the books.
+  mozilla::OffTheBooksMutex mCamerasMutex;
+
+  // This is owned by the IPC code, and the same code controls the lifetime.
+  // It will set and clear this pointer as appropriate in setup/teardown.
+  // We'd normally make this a WeakPtr but unfortunately the IPC code already
+  // uses the WeakPtr mixin in a protected base class of CamerasChild, and in
+  // any case the object becomes unusable as soon as IPC is tearing down, which
+  // will be before actual destruction.
+  CamerasChild* mCameras;
+  nsCOMPtr<nsIThread> mCamerasChildThread;
+  nsCOMPtr<nsIThread> mFakeDeviceChangeEventThread;
+};
+
+// Get a pointer to a CamerasChild object we can use to do IPC with.
+// This does everything needed to set up, including starting the IPC
+// channel with PBackground, blocking until thats done, and starting the
+// thread to do IPC on. This will fail if we're in shutdown. On success
+// it will set up the CamerasSingleton.
+CamerasChild* GetCamerasChild();
+
+CamerasChild* GetCamerasChildIfExists();
+
+// Shut down the IPC channel and everything associated, like WebRTC.
+// This is a static call because the CamerasChild object may not even
+// be alive when we're called.
+void Shutdown(void);
+
+// Obtain the CamerasChild object (if possible, i.e. not shutting down),
+// and maintain a grip on the object for the duration of the call.
+template <class MEM_FUN, class... ARGS>
+int GetChildAndCall(MEM_FUN&& f, ARGS&&... args)
+{
+  OffTheBooksMutexAutoLock lock(CamerasSingleton::Mutex());
+  CamerasChild* child = GetCamerasChild();
+  if (child) {
+    return (child->*f)(mozilla::Forward<ARGS>(args)...);
+  } else {
+    return -1;
+  }
+}
+
+class CamerasChild final : public PCamerasChild
+                          ,public DeviceChangeCallback
+{
+  friend class mozilla::ipc::BackgroundChildImpl;
+  template <class T> friend class mozilla::camera::LockAndDispatch;
+
+public:
+  // We are owned by the PBackground thread only. CamerasSingleton
+  // takes a non-owning reference.
+  NS_INLINE_DECL_REFCOUNTING(CamerasChild)
+
+  // IPC messages recevied, received on the PBackground thread
+  // these are the actual callbacks with data
+  virtual bool RecvDeliverFrame(const CaptureEngine&, const int&, mozilla::ipc::Shmem&&,
+                                const size_t&, const uint32_t&, const int64_t&,
+                                const int64_t&) override;
+  virtual bool RecvFrameSizeChange(const CaptureEngine&, const int&,
+                                   const int& w, const int& h) override;
+
+  virtual bool RecvDeviceChange() override;
+  virtual int AddDeviceChangeCallback(DeviceChangeCallback* aCallback) override;
+  int SetFakeDeviceChangeEvents();
+
+  // these are response messages to our outgoing requests
+  virtual bool RecvReplyNumberOfCaptureDevices(const int&) override;
+  virtual bool RecvReplyNumberOfCapabilities(const int&) override;
+  virtual bool RecvReplyAllocateCaptureDevice(const int&) override;
+  virtual bool RecvReplyGetCaptureCapability(const CaptureCapability& capability) override;
+  virtual bool RecvReplyGetCaptureDevice(const nsCString& device_name,
+                                         const nsCString& device_id,
+                                         const bool& scary) override;
+  virtual bool RecvReplyFailure(void) override;
+  virtual bool RecvReplySuccess(void) override;
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  // the webrtc.org ViECapture calls are mirrored here, but with access
+  // to a specific PCameras instance to communicate over. These also
+  // run on the MediaManager thread
+  int NumberOfCaptureDevices(CaptureEngine aCapEngine);
+  int NumberOfCapabilities(CaptureEngine aCapEngine,
+                           const char* deviceUniqueIdUTF8);
+  int ReleaseCaptureDevice(CaptureEngine aCapEngine,
+                           const int capture_id);
+  int StartCapture(CaptureEngine aCapEngine,
+                   const int capture_id, webrtc::CaptureCapability& capability,
+                   webrtc::ExternalRenderer* func);
+  int StopCapture(CaptureEngine aCapEngine, const int capture_id);
+  int AllocateCaptureDevice(CaptureEngine aCapEngine,
+                            const char* unique_idUTF8,
+                            const unsigned int unique_idUTF8Length,
+                            int& capture_id,
+                            const nsACString& aOrigin);
+  int GetCaptureCapability(CaptureEngine aCapEngine,
+                           const char* unique_idUTF8,
+                           const unsigned int capability_number,
+                           webrtc::CaptureCapability& capability);
+  int GetCaptureDevice(CaptureEngine aCapEngine,
+                       unsigned int list_number, char* device_nameUTF8,
+                       const unsigned int device_nameUTF8Length,
+                       char* unique_idUTF8,
+                       const unsigned int unique_idUTF8Length,
+                       bool* scary = nullptr);
+  void ShutdownAll();
+  int EnsureInitialized(CaptureEngine aCapEngine);
+
+  webrtc::ExternalRenderer* Callback(CaptureEngine aCapEngine, int capture_id);
+
+private:
+  CamerasChild();
+  ~CamerasChild();
+  // Dispatch a Runnable to the PCamerasParent, by executing it on the
+  // decidecated Cameras IPC/PBackground thread.
+  bool DispatchToParent(nsIRunnable* aRunnable,
+                        MonitorAutoLock& aMonitor);
+  void AddCallback(const CaptureEngine aCapEngine, const int capture_id,
+                   webrtc::ExternalRenderer* render);
+  void RemoveCallback(const CaptureEngine aCapEngine, const int capture_id);
+  void ShutdownParent();
+  void ShutdownChild();
+
+  nsTArray<CapturerElement> mCallbacks;
+  // Protects the callback arrays
+  Mutex mCallbackMutex;
+
+  bool mIPCIsAlive;
+
+  // Hold to prevent multiple outstanding requests. We don't use
+  // request IDs so we only support one at a time. Don't want try
+  // to use the webrtc.org API from multiple threads simultanously.
+  // The monitor below isn't sufficient for this, as it will drop
+  // the lock when Wait-ing for a response, allowing us to send a new
+  // request. The Notify on receiving the response will then unblock
+  // both waiters and one will be guaranteed to get the wrong result.
+  // Take this one before taking mReplyMonitor.
+  Mutex mRequestMutex;
+  // Hold to wait for an async response to our calls
+  Monitor mReplyMonitor;
+  // Async response valid?
+  bool mReceivedReply;
+  // Async responses data contents;
+  bool mReplySuccess;
+  int mReplyInteger;
+  webrtc::CaptureCapability mReplyCapability;
+  nsCString mReplyDeviceName;
+  nsCString mReplyDeviceID;
+  bool mReplyScary;
+};
+
+} // namespace camera
+} // namespace mozilla
+
+#endif  // mozilla_CamerasChild_h
diff --git a/dom/media/systemservices/CamerasParent.cpp b/dom/media/systemservices/CamerasParent.cpp
new file mode 100644
index 0000000000..808a076d7e
--- /dev/null
+++ b/dom/media/systemservices/CamerasParent.cpp
@@ -0,0 +1,1094 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CamerasParent.h"
+#include "MediaEngine.h"
+#include "MediaUtils.h"
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Unused.h"
+#include "mozilla/Services.h"
+#include "mozilla/Logging.h"
+#include "mozilla/ipc/BackgroundParent.h"
+#include "mozilla/Preferences.h"
+#include "nsIPermissionManager.h"
+#include "nsThreadUtils.h"
+#include "nsXPCOM.h"
+#include "nsNetUtil.h"
+
+#include "webrtc/common_video/libyuv/include/webrtc_libyuv.h"
+
+#if defined(_WIN32)
+#include <process.h>
+#define getpid() _getpid()
+#endif
+
+#undef LOG
+#undef LOG_ENABLED
+mozilla::LazyLogModule gCamerasParentLog("CamerasParent");
+#define LOG(args) MOZ_LOG(gCamerasParentLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gCamerasParentLog, mozilla::LogLevel::Debug)
+
+namespace mozilla {
+namespace camera {
+
+// 3 threads are involved in this code:
+// - the main thread for some setups, and occassionally for video capture setup
+//   calls that don't work correctly elsewhere.
+// - the IPC thread on which PBackground is running and which receives and
+//   sends messages
+// - a thread which will execute the actual (possibly slow) camera access
+//   called "VideoCapture". On Windows this is a thread with an event loop
+//   suitable for UI access.
+
+// InputObserver is owned by CamerasParent, and it has a ref to CamerasParent
+void InputObserver::DeviceChange() {
+  LOG((__PRETTY_FUNCTION__));
+  MOZ_ASSERT(mParent);
+
+  RefPtr<InputObserver> self(this);
+  RefPtr<nsIRunnable> ipc_runnable =
+    media::NewRunnableFrom([self]() -> nsresult {
+      if (self->mParent->IsShuttingDown()) {
+        return NS_ERROR_FAILURE;
+      }
+      Unused << self->mParent->SendDeviceChange();
+      return NS_OK;
+    });
+
+  nsIThread* thread = mParent->GetBackgroundThread();
+  MOZ_ASSERT(thread != nullptr);
+  thread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+};
+
+class FrameSizeChangeRunnable : public Runnable {
+public:
+  FrameSizeChangeRunnable(CamerasParent *aParent, CaptureEngine capEngine,
+                          int cap_id, unsigned int aWidth, unsigned int aHeight)
+    : mParent(aParent), mCapEngine(capEngine), mCapId(cap_id),
+      mWidth(aWidth), mHeight(aHeight) {}
+
+  NS_IMETHOD Run() override {
+    if (mParent->IsShuttingDown()) {
+      // Communication channel is being torn down
+      LOG(("FrameSizeChangeRunnable is active without active Child"));
+      mResult = 0;
+      return NS_OK;
+    }
+    if (!mParent->SendFrameSizeChange(mCapEngine, mCapId, mWidth, mHeight)) {
+      mResult = -1;
+    } else {
+      mResult = 0;
+    }
+    return NS_OK;
+  }
+
+  int GetResult() {
+    return mResult;
+  }
+
+private:
+  RefPtr<CamerasParent> mParent;
+  CaptureEngine mCapEngine;
+  int mCapId;
+  unsigned int mWidth;
+  unsigned int mHeight;
+  int mResult;
+};
+
+int
+CallbackHelper::FrameSizeChange(unsigned int w, unsigned int h,
+                                unsigned int streams)
+{
+  LOG(("CallbackHelper Video FrameSizeChange: %ux%u", w, h));
+  RefPtr<FrameSizeChangeRunnable> runnable =
+    new FrameSizeChangeRunnable(mParent, mCapEngine, mCapturerId, w, h);
+  MOZ_ASSERT(mParent);
+  nsIThread * thread = mParent->GetBackgroundThread();
+  MOZ_ASSERT(thread != nullptr);
+  thread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  return 0;
+}
+
+class DeliverFrameRunnable : public Runnable {
+public:
+  DeliverFrameRunnable(CamerasParent *aParent,
+                       CaptureEngine engine,
+                       int cap_id,
+                       ShmemBuffer buffer,
+                       unsigned char* altbuffer,
+                       size_t size,
+                       uint32_t time_stamp,
+                       int64_t ntp_time,
+                       int64_t render_time)
+    : mParent(aParent), mCapEngine(engine), mCapId(cap_id), mBuffer(Move(buffer)),
+      mSize(size), mTimeStamp(time_stamp), mNtpTime(ntp_time),
+      mRenderTime(render_time) {
+    // No ShmemBuffer (of the right size) was available, so make an
+    // extra buffer here.  We have no idea when we are going to run and
+    // it will be potentially long after the webrtc frame callback has
+    // returned, so the copy needs to be no later than here.
+    // We will need to copy this back into a Shmem later on so we prefer
+    // using ShmemBuffers to avoid the extra copy.
+    if (altbuffer != nullptr) {
+      mAlternateBuffer.reset(new unsigned char[size]);
+      memcpy(mAlternateBuffer.get(), altbuffer, size);
+    }
+  };
+
+  NS_IMETHOD Run() override {
+    if (mParent->IsShuttingDown()) {
+      // Communication channel is being torn down
+      mResult = 0;
+      return NS_OK;
+    }
+    if (!mParent->DeliverFrameOverIPC(mCapEngine, mCapId,
+                                      Move(mBuffer), mAlternateBuffer.get(),
+                                      mSize, mTimeStamp,
+                                      mNtpTime, mRenderTime)) {
+      mResult = -1;
+    } else {
+      mResult = 0;
+    }
+    return NS_OK;
+  }
+
+  int GetResult() {
+    return mResult;
+  }
+
+private:
+  RefPtr<CamerasParent> mParent;
+  CaptureEngine mCapEngine;
+  int mCapId;
+  ShmemBuffer mBuffer;
+  mozilla::UniquePtr<unsigned char[]> mAlternateBuffer;
+  size_t mSize;
+  uint32_t mTimeStamp;
+  int64_t mNtpTime;
+  int64_t mRenderTime;
+  int mResult;
+};
+
+NS_IMPL_ISUPPORTS(CamerasParent, nsIObserver)
+
+NS_IMETHODIMP
+CamerasParent::Observe(nsISupports *aSubject,
+                       const char *aTopic,
+                       const char16_t *aData)
+{
+  MOZ_ASSERT(!strcmp(aTopic, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID));
+  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+  MOZ_ASSERT(obs);
+  obs->RemoveObserver(this, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID);
+  StopVideoCapture();
+  return NS_OK;
+}
+
+nsresult
+CamerasParent::DispatchToVideoCaptureThread(Runnable* event)
+{
+  // Don't try to dispatch if we're already on the right thread.
+  // There's a potential deadlock because the mThreadMonitor is likely
+  // to be taken already.
+  MOZ_ASSERT(!mVideoCaptureThread ||
+             mVideoCaptureThread->thread_id() != PlatformThread::CurrentId());
+
+  MonitorAutoLock lock(mThreadMonitor);
+
+  while(mChildIsAlive && mWebRTCAlive &&
+        (!mVideoCaptureThread || !mVideoCaptureThread->IsRunning())) {
+    mThreadMonitor.Wait();
+  }
+  if (!mVideoCaptureThread || !mVideoCaptureThread->IsRunning()) {
+    return NS_ERROR_FAILURE;
+  }
+  RefPtr<Runnable> addrefedEvent = event;
+  mVideoCaptureThread->message_loop()->PostTask(addrefedEvent.forget());
+  return NS_OK;
+}
+
+void
+CamerasParent::StopVideoCapture()
+{
+  LOG((__PRETTY_FUNCTION__));
+  // We are called from the main thread (xpcom-shutdown) or
+  // from PBackground (when the Actor shuts down).
+  // Shut down the WebRTC stack (on the capture thread)
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self]() -> nsresult {
+      MonitorAutoLock lock(self->mThreadMonitor);
+      self->CloseEngines();
+      self->mThreadMonitor.NotifyAll();
+      return NS_OK;
+    });
+  DebugOnly<nsresult> rv = DispatchToVideoCaptureThread(webrtc_runnable);
+#ifdef DEBUG
+  // It's ok for the dispatch to fail if the cleanup it has to do
+  // has been done already.
+  MOZ_ASSERT(NS_SUCCEEDED(rv) || !mWebRTCAlive);
+#endif
+  // Hold here until the WebRTC thread is gone. We need to dispatch
+  // the thread deletion *now*, or there will be no more possibility
+  // to get to the main thread.
+  MonitorAutoLock lock(mThreadMonitor);
+  while (mWebRTCAlive) {
+    mThreadMonitor.Wait();
+  }
+  // After closing the WebRTC stack, clean up the
+  // VideoCapture thread.
+  if (self->mVideoCaptureThread) {
+    base::Thread *thread = self->mVideoCaptureThread;
+    self->mVideoCaptureThread = nullptr;
+    RefPtr<Runnable> threadShutdown =
+      media::NewRunnableFrom([thread]() -> nsresult {
+        if (thread->IsRunning()) {
+          thread->Stop();
+        }
+        delete thread;
+        return NS_OK;
+      });
+    if (NS_FAILED(NS_DispatchToMainThread(threadShutdown))) {
+      LOG(("Could not dispatch VideoCaptureThread destruction"));
+    }
+  }
+}
+
+int
+CamerasParent::DeliverFrameOverIPC(CaptureEngine cap_engine,
+                                   int cap_id,
+                                   ShmemBuffer buffer,
+                                   unsigned char* altbuffer,
+                                   size_t size,
+                                   uint32_t time_stamp,
+                                   int64_t ntp_time,
+                                   int64_t render_time)
+{
+  // No ShmemBuffers were available, so construct one now of the right size
+  // and copy into it. That is an extra copy, but we expect this to be
+  // the exceptional case, because we just assured the next call *will* have a
+  // buffer of the right size.
+  if (altbuffer != nullptr) {
+    // Get a shared memory buffer from the pool, at least size big
+    ShmemBuffer shMemBuff = mShmemPool.Get(this, size);
+
+    if (!shMemBuff.Valid()) {
+      LOG(("No usable Video shmem in DeliverFrame (out of buffers?)"));
+      // We can skip this frame if we run out of buffers, it's not a real error.
+      return 0;
+    }
+
+    // get() and Size() check for proper alignment of the segment
+    memcpy(shMemBuff.GetBytes(), altbuffer, size);
+
+    if (!SendDeliverFrame(cap_engine, cap_id,
+                          shMemBuff.Get(), size,
+                          time_stamp, ntp_time, render_time)) {
+      return -1;
+    }
+  } else {
+    MOZ_ASSERT(buffer.Valid());
+    // ShmemBuffer was available, we're all good. A single copy happened
+    // in the original webrtc callback.
+    if (!SendDeliverFrame(cap_engine, cap_id,
+                          buffer.Get(), size,
+                          time_stamp, ntp_time, render_time)) {
+      return -1;
+    }
+  }
+
+  return 0;
+}
+
+ShmemBuffer
+CamerasParent::GetBuffer(size_t aSize)
+{
+  return mShmemPool.GetIfAvailable(aSize);
+}
+
+int
+CallbackHelper::DeliverFrame(unsigned char* buffer,
+                             size_t size,
+                             uint32_t time_stamp,
+                             int64_t ntp_time,
+                             int64_t render_time,
+                             void *handle)
+{
+  // Get a shared memory buffer to copy the frame data into
+  ShmemBuffer shMemBuffer = mParent->GetBuffer(size);
+  if (!shMemBuffer.Valid()) {
+    // Either we ran out of buffers or they're not the right size yet
+    LOG(("Correctly sized Video shmem not available in DeliverFrame"));
+    // We will do the copy into a(n extra) temporary buffer inside
+    // the DeliverFrameRunnable constructor.
+  } else {
+    // Shared memory buffers of the right size are available, do the copy here.
+    memcpy(shMemBuffer.GetBytes(), buffer, size);
+    // Mark the original buffer as cleared.
+    buffer = nullptr;
+  }
+  RefPtr<DeliverFrameRunnable> runnable =
+    new DeliverFrameRunnable(mParent, mCapEngine, mCapturerId,
+                             Move(shMemBuffer), buffer, size, time_stamp,
+                             ntp_time, render_time);
+  MOZ_ASSERT(mParent);
+  nsIThread* thread = mParent->GetBackgroundThread();
+  MOZ_ASSERT(thread != nullptr);
+  thread->Dispatch(runnable, NS_DISPATCH_NORMAL);
+  return 0;
+}
+// XXX!!! FIX THIS -- we should move to pure DeliverI420Frame
+int
+CallbackHelper::DeliverI420Frame(const webrtc::I420VideoFrame& webrtc_frame)
+{
+  return DeliverFrame(const_cast<uint8_t*>(webrtc_frame.buffer(webrtc::kYPlane)),
+                      CalcBufferSize(webrtc::kI420, webrtc_frame.width(), webrtc_frame.height()),
+                      webrtc_frame.timestamp(),
+                      webrtc_frame.ntp_time_ms(),
+                      webrtc_frame.render_time_ms(),
+                      (void*) webrtc_frame.native_handle());
+}
+
+bool
+CamerasParent::RecvReleaseFrame(mozilla::ipc::Shmem&& s) {
+  mShmemPool.Put(ShmemBuffer(s));
+  return true;
+}
+
+bool
+CamerasParent::SetupEngine(CaptureEngine aCapEngine)
+{
+  MOZ_ASSERT(mVideoCaptureThread->thread_id() == PlatformThread::CurrentId());
+  EngineHelper *helper = &mEngines[aCapEngine];
+
+  // Already initialized
+  if (helper->mEngine) {
+    return true;
+  }
+
+  webrtc::CaptureDeviceInfo *captureDeviceInfo = nullptr;
+
+  switch (aCapEngine) {
+  case ScreenEngine:
+    captureDeviceInfo =
+      new webrtc::CaptureDeviceInfo(webrtc::CaptureDeviceType::Screen);
+    break;
+  case BrowserEngine:
+    captureDeviceInfo =
+      new webrtc::CaptureDeviceInfo(webrtc::CaptureDeviceType::Browser);
+    break;
+  case WinEngine:
+    captureDeviceInfo =
+      new webrtc::CaptureDeviceInfo(webrtc::CaptureDeviceType::Window);
+    break;
+  case AppEngine:
+    captureDeviceInfo =
+      new webrtc::CaptureDeviceInfo(webrtc::CaptureDeviceType::Application);
+    break;
+  case CameraEngine:
+    captureDeviceInfo =
+      new webrtc::CaptureDeviceInfo(webrtc::CaptureDeviceType::Camera);
+    break;
+  default:
+    LOG(("Invalid webrtc Video engine"));
+    MOZ_CRASH();
+    break;
+  }
+
+  helper->mConfig.Set<webrtc::CaptureDeviceInfo>(captureDeviceInfo);
+  helper->mEngine = webrtc::VideoEngine::Create(helper->mConfig);
+
+  if (!helper->mEngine) {
+    LOG(("VideoEngine::Create failed"));
+    return false;
+  }
+
+  helper->mPtrViEBase = webrtc::ViEBase::GetInterface(helper->mEngine);
+  if (!helper->mPtrViEBase) {
+    LOG(("ViEBase::GetInterface failed"));
+    return false;
+  }
+
+  if (helper->mPtrViEBase->Init() < 0) {
+    LOG(("ViEBase::Init failed"));
+    return false;
+  }
+
+  helper->mPtrViECapture = webrtc::ViECapture::GetInterface(helper->mEngine);
+  if (!helper->mPtrViECapture) {
+    LOG(("ViECapture::GetInterface failed"));
+    return false;
+  }
+
+  RefPtr<InputObserver>* observer = mObservers.AppendElement(new InputObserver(this));
+
+#ifdef DEBUG
+  MOZ_ASSERT(0 == helper->mPtrViECapture->RegisterInputObserver(observer->get()));
+#else
+  helper->mPtrViECapture->RegisterInputObserver(observer->get());
+#endif
+
+  helper->mPtrViERender = webrtc::ViERender::GetInterface(helper->mEngine);
+  if (!helper->mPtrViERender) {
+    LOG(("ViERender::GetInterface failed"));
+    return false;
+  }
+
+  return true;
+}
+
+void
+CamerasParent::CloseEngines()
+{
+  LOG((__PRETTY_FUNCTION__));
+  if (!mWebRTCAlive) {
+    return;
+  }
+  MOZ_ASSERT(mVideoCaptureThread->thread_id() == PlatformThread::CurrentId());
+
+  // Stop the callers
+  while (mCallbacks.Length()) {
+    auto capEngine = mCallbacks[0]->mCapEngine;
+    auto capNum = mCallbacks[0]->mCapturerId;
+    LOG(("Forcing shutdown of engine %d, capturer %d", capEngine, capNum));
+    StopCapture(capEngine, capNum);
+    Unused << ReleaseCaptureDevice(capEngine, capNum);
+  }
+
+  for (int i = 0; i < CaptureEngine::MaxEngine; i++) {
+    if (mEngines[i].mEngineIsRunning) {
+      LOG(("Being closed down while engine %d is running!", i));
+    }
+    if (mEngines[i].mPtrViERender) {
+      mEngines[i].mPtrViERender->Release();
+      mEngines[i].mPtrViERender = nullptr;
+    }
+    if (mEngines[i].mPtrViECapture) {
+#ifdef DEBUG
+      MOZ_ASSERT(0 == mEngines[i].mPtrViECapture->DeregisterInputObserver());
+#else
+      mEngines[i].mPtrViECapture->DeregisterInputObserver();
+#endif
+
+      mEngines[i].mPtrViECapture->Release();
+        mEngines[i].mPtrViECapture = nullptr;
+    }
+    if(mEngines[i].mPtrViEBase) {
+      mEngines[i].mPtrViEBase->Release();
+      mEngines[i].mPtrViEBase = nullptr;
+    }
+    if (mEngines[i].mEngine) {
+      mEngines[i].mEngine->SetTraceCallback(nullptr);
+      webrtc::VideoEngine::Delete(mEngines[i].mEngine);
+      mEngines[i].mEngine = nullptr;
+    }
+  }
+
+  mObservers.Clear();
+
+  mWebRTCAlive = false;
+}
+
+bool
+CamerasParent::EnsureInitialized(int aEngine)
+{
+  LOG((__PRETTY_FUNCTION__));
+  // We're shutting down, don't try to do new WebRTC ops.
+  if (!mWebRTCAlive) {
+    return false;
+  }
+  CaptureEngine capEngine = static_cast<CaptureEngine>(aEngine);
+  if (!SetupEngine(capEngine)) {
+    LOG(("CamerasParent failed to initialize engine"));
+    return false;
+  }
+
+  return true;
+}
+
+// Dispatch the runnable to do the camera operation on the
+// specific Cameras thread, preventing us from blocking, and
+// chain a runnable to send back the result on the IPC thread.
+// It would be nice to get rid of the code duplication here,
+// perhaps via Promises.
+bool
+CamerasParent::RecvNumberOfCaptureDevices(const CaptureEngine& aCapEngine)
+{
+  LOG((__PRETTY_FUNCTION__));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine]() -> nsresult {
+      int num = -1;
+      if (self->EnsureInitialized(aCapEngine)) {
+        num = self->mEngines[aCapEngine].mPtrViECapture->NumberOfCaptureDevices();
+      }
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, num]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          if (num < 0) {
+            LOG(("RecvNumberOfCaptureDevices couldn't find devices"));
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          } else {
+            LOG(("RecvNumberOfCaptureDevices: %d", num));
+            Unused << self->SendReplyNumberOfCaptureDevices(num);
+            return NS_OK;
+          }
+        });
+        self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+bool
+CamerasParent::RecvEnsureInitialized(const CaptureEngine& aCapEngine)
+{
+  LOG((__PRETTY_FUNCTION__));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine]() -> nsresult {
+      bool result = self->EnsureInitialized(aCapEngine);
+
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, result]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          if (!result) {
+            LOG(("RecvEnsureInitialized failed"));
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          } else {
+            LOG(("RecvEnsureInitialized succeeded"));
+            Unused << self->SendReplySuccess();
+            return NS_OK;
+          }
+        });
+        self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+bool
+CamerasParent::RecvNumberOfCapabilities(const CaptureEngine& aCapEngine,
+                                        const nsCString& unique_id)
+{
+  LOG((__PRETTY_FUNCTION__));
+  LOG(("Getting caps for %s", unique_id.get()));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, unique_id, aCapEngine]() -> nsresult {
+      int num = -1;
+      if (self->EnsureInitialized(aCapEngine)) {
+        num =
+          self->mEngines[aCapEngine].mPtrViECapture->NumberOfCapabilities(
+            unique_id.get(),
+            MediaEngineSource::kMaxUniqueIdLength);
+      }
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, num]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          if (num < 0) {
+            LOG(("RecvNumberOfCapabilities couldn't find capabilities"));
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          } else {
+            LOG(("RecvNumberOfCapabilities: %d", num));
+          }
+          Unused << self->SendReplyNumberOfCapabilities(num);
+          return NS_OK;
+        });
+      self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+bool
+CamerasParent::RecvGetCaptureCapability(const CaptureEngine& aCapEngine,
+                                        const nsCString& unique_id,
+                                        const int& num)
+{
+  LOG((__PRETTY_FUNCTION__));
+  LOG(("RecvGetCaptureCapability: %s %d", unique_id.get(), num));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, unique_id, aCapEngine, num]() -> nsresult {
+      webrtc::CaptureCapability webrtcCaps;
+      int error = -1;
+      if (self->EnsureInitialized(aCapEngine)) {
+        error = self->mEngines[aCapEngine].mPtrViECapture->GetCaptureCapability(
+          unique_id.get(), MediaEngineSource::kMaxUniqueIdLength, num, webrtcCaps);
+      }
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, webrtcCaps, error]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          CaptureCapability capCap(webrtcCaps.width,
+                                   webrtcCaps.height,
+                                   webrtcCaps.maxFPS,
+                                   webrtcCaps.expectedCaptureDelay,
+                                   webrtcCaps.rawType,
+                                   webrtcCaps.codecType,
+                                   webrtcCaps.interlaced);
+          LOG(("Capability: %u %u %u %u %d %d",
+               webrtcCaps.width,
+               webrtcCaps.height,
+               webrtcCaps.maxFPS,
+               webrtcCaps.expectedCaptureDelay,
+               webrtcCaps.rawType,
+               webrtcCaps.codecType));
+          if (error) {
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          }
+          Unused << self->SendReplyGetCaptureCapability(capCap);
+          return NS_OK;
+        });
+      self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+bool
+CamerasParent::RecvGetCaptureDevice(const CaptureEngine& aCapEngine,
+                                    const int& aListNumber)
+{
+  LOG((__PRETTY_FUNCTION__));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine, aListNumber]() -> nsresult {
+      char deviceName[MediaEngineSource::kMaxDeviceNameLength];
+      char deviceUniqueId[MediaEngineSource::kMaxUniqueIdLength];
+      nsCString name;
+      nsCString uniqueId;
+      int devicePid = 0;
+      int error = -1;
+      if (self->EnsureInitialized(aCapEngine)) {
+          error = self->mEngines[aCapEngine].mPtrViECapture->GetCaptureDevice(aListNumber,
+                                                                              deviceName,
+                                                                              sizeof(deviceName),
+                                                                              deviceUniqueId,
+                                                                              sizeof(deviceUniqueId),
+                                                                              &devicePid);
+      }
+      if (!error) {
+        name.Assign(deviceName);
+        uniqueId.Assign(deviceUniqueId);
+      }
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, error, name, uniqueId, devicePid]() {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          if (error) {
+            LOG(("GetCaptureDevice failed: %d", error));
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          }
+          bool scary = (devicePid == getpid());
+
+          LOG(("Returning %s name %s id (pid = %d)%s", name.get(),
+               uniqueId.get(), devicePid, (scary? " (scary)" : "")));
+          Unused << self->SendReplyGetCaptureDevice(name, uniqueId, scary);
+          return NS_OK;
+        });
+      self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+static nsresult
+GetPrincipalFromOrigin(const nsACString& aOrigin, nsIPrincipal** aPrincipal)
+{
+  nsAutoCString originNoSuffix;
+  mozilla::PrincipalOriginAttributes attrs;
+  if (!attrs.PopulateFromOrigin(aOrigin, originNoSuffix)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = NS_NewURI(getter_AddRefs(uri), originNoSuffix);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIPrincipal> principal = mozilla::BasePrincipal::CreateCodebasePrincipal(uri, attrs);
+  principal.forget(aPrincipal);
+  return NS_OK;
+}
+
+// Find out whether the given origin has permission to use the
+// camera. If the permission is not persistent, we'll make it
+// a one-shot by removing the (session) permission.
+static bool
+HasCameraPermission(const nsCString& aOrigin)
+{
+  // Name used with nsIPermissionManager
+  static const char* cameraPermission = "MediaManagerVideo";
+  bool allowed = false;
+  nsresult rv;
+  nsCOMPtr<nsIPermissionManager> mgr =
+    do_GetService(NS_PERMISSIONMANAGER_CONTRACTID, &rv);
+  if (NS_SUCCEEDED(rv)) {
+    nsCOMPtr<nsIIOService> ioServ(do_GetIOService());
+    nsCOMPtr<nsIURI> uri;
+    rv = ioServ->NewURI(aOrigin, nullptr, nullptr, getter_AddRefs(uri));
+    if (NS_SUCCEEDED(rv)) {
+      // Permanent permissions are only retrievable via principal, not uri
+      nsCOMPtr<nsIPrincipal> principal;
+      rv = GetPrincipalFromOrigin(aOrigin, getter_AddRefs(principal));
+      if (NS_SUCCEEDED(rv)) {
+        uint32_t video = nsIPermissionManager::UNKNOWN_ACTION;
+        rv = mgr->TestExactPermissionFromPrincipal(principal,
+                                                   cameraPermission,
+                                                   &video);
+        if (NS_SUCCEEDED(rv)) {
+          allowed = (video == nsIPermissionManager::ALLOW_ACTION);
+        }
+        // Session permissions are removed after one use.
+        if (allowed) {
+          mgr->RemoveFromPrincipal(principal, cameraPermission);
+        }
+      }
+    }
+  }
+  return allowed;
+}
+
+bool
+CamerasParent::RecvAllocateCaptureDevice(const CaptureEngine& aCapEngine,
+                                         const nsCString& unique_id,
+                                         const nsCString& aOrigin)
+{
+  LOG(("%s: Verifying permissions for %s", __PRETTY_FUNCTION__, aOrigin.get()));
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> mainthread_runnable =
+    media::NewRunnableFrom([self, aCapEngine, unique_id, aOrigin]() -> nsresult {
+      // Verify whether the claimed origin has received permission
+      // to use the camera, either persistently or this session (one shot).
+      bool allowed = HasCameraPermission(aOrigin);
+      if (!allowed) {
+        // Developer preference for turning off permission check.
+        if (Preferences::GetBool("media.navigator.permission.disabled", false)
+            || Preferences::GetBool("media.navigator.permission.fake")) {
+          allowed = true;
+          LOG(("No permission but checks are disabled or fake sources active"));
+        } else {
+          LOG(("No camera permission for this origin"));
+        }
+      }
+      // After retrieving the permission (or not) on the main thread,
+      // bounce to the WebRTC thread to allocate the device (or not),
+      // then bounce back to the IPC thread for the reply to content.
+      RefPtr<Runnable> webrtc_runnable =
+      media::NewRunnableFrom([self, allowed, aCapEngine, unique_id]() -> nsresult {
+        int numdev = -1;
+        int error = -1;
+        if (allowed && self->EnsureInitialized(aCapEngine)) {
+          error = self->mEngines[aCapEngine].mPtrViECapture->AllocateCaptureDevice(
+                    unique_id.get(), MediaEngineSource::kMaxUniqueIdLength, numdev);
+        }
+        RefPtr<nsIRunnable> ipc_runnable =
+          media::NewRunnableFrom([self, numdev, error]() -> nsresult {
+            if (self->IsShuttingDown()) {
+              return NS_ERROR_FAILURE;
+            }
+            if (error) {
+              Unused << self->SendReplyFailure();
+              return NS_ERROR_FAILURE;
+            } else {
+              LOG(("Allocated device nr %d", numdev));
+              Unused << self->SendReplyAllocateCaptureDevice(numdev);
+              return NS_OK;
+            }
+          });
+        self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+        return NS_OK;
+        });
+      self->DispatchToVideoCaptureThread(webrtc_runnable);
+      return NS_OK;
+    });
+  NS_DispatchToMainThread(mainthread_runnable);
+  return true;
+}
+
+int
+CamerasParent::ReleaseCaptureDevice(const CaptureEngine& aCapEngine,
+                                    const int& capnum)
+{
+  int error = -1;
+  if (EnsureInitialized(aCapEngine)) {
+    error = mEngines[aCapEngine].mPtrViECapture->ReleaseCaptureDevice(capnum);
+  }
+  return error;
+}
+
+bool
+CamerasParent::RecvReleaseCaptureDevice(const CaptureEngine& aCapEngine,
+                                        const int& numdev)
+{
+  LOG((__PRETTY_FUNCTION__));
+  LOG(("RecvReleaseCamera device nr %d", numdev));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine, numdev]() -> nsresult {
+      int error = self->ReleaseCaptureDevice(aCapEngine, numdev);
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, error, numdev]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            LOG(("In Shutdown, not Releasing"));
+            return NS_ERROR_FAILURE;
+          }
+          if (error) {
+            Unused << self->SendReplyFailure();
+            LOG(("Failed to free device nr %d", numdev));
+            return NS_ERROR_FAILURE;
+          } else {
+            Unused << self->SendReplySuccess();
+            LOG(("Freed device nr %d", numdev));
+            return NS_OK;
+          }
+        });
+      self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+bool
+CamerasParent::RecvStartCapture(const CaptureEngine& aCapEngine,
+                                const int& capnum,
+                                const CaptureCapability& ipcCaps)
+{
+  LOG((__PRETTY_FUNCTION__));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine, capnum, ipcCaps]() -> nsresult {
+      CallbackHelper** cbh;
+      webrtc::ExternalRenderer* render;
+      EngineHelper* helper = nullptr;
+      int error = -1;
+      if (self->EnsureInitialized(aCapEngine)) {
+        cbh = self->mCallbacks.AppendElement(
+          new CallbackHelper(static_cast<CaptureEngine>(aCapEngine), capnum, self));
+        render = static_cast<webrtc::ExternalRenderer*>(*cbh);
+
+        helper = &self->mEngines[aCapEngine];
+        error =
+          helper->mPtrViERender->AddRenderer(capnum, webrtc::kVideoI420, render);
+        if (!error) {
+          error = helper->mPtrViERender->StartRender(capnum);
+        }
+
+        webrtc::CaptureCapability capability;
+        capability.width = ipcCaps.width();
+        capability.height = ipcCaps.height();
+        capability.maxFPS = ipcCaps.maxFPS();
+        capability.expectedCaptureDelay = ipcCaps.expectedCaptureDelay();
+        capability.rawType = static_cast<webrtc::RawVideoType>(ipcCaps.rawType());
+        capability.codecType = static_cast<webrtc::VideoCodecType>(ipcCaps.codecType());
+        capability.interlaced = ipcCaps.interlaced();
+
+        if (!error) {
+          error = helper->mPtrViECapture->StartCapture(capnum, capability);
+        }
+        if (!error) {
+          helper->mEngineIsRunning = true;
+        }
+      }
+      RefPtr<nsIRunnable> ipc_runnable =
+        media::NewRunnableFrom([self, error]() -> nsresult {
+          if (self->IsShuttingDown()) {
+            return NS_ERROR_FAILURE;
+          }
+          if (!error) {
+            Unused << self->SendReplySuccess();
+            return NS_OK;
+          } else {
+            Unused << self->SendReplyFailure();
+            return NS_ERROR_FAILURE;
+          }
+        });
+      self->mPBackgroundThread->Dispatch(ipc_runnable, NS_DISPATCH_NORMAL);
+      return NS_OK;
+    });
+  DispatchToVideoCaptureThread(webrtc_runnable);
+  return true;
+}
+
+void
+CamerasParent::StopCapture(const CaptureEngine& aCapEngine,
+                           const int& capnum)
+{
+  if (EnsureInitialized(aCapEngine)) {
+    mEngines[aCapEngine].mPtrViECapture->StopCapture(capnum);
+    mEngines[aCapEngine].mPtrViERender->StopRender(capnum);
+    mEngines[aCapEngine].mPtrViERender->RemoveRenderer(capnum);
+    mEngines[aCapEngine].mEngineIsRunning = false;
+
+    for (size_t i = 0; i < mCallbacks.Length(); i++) {
+      if (mCallbacks[i]->mCapEngine == aCapEngine
+          && mCallbacks[i]->mCapturerId == capnum) {
+        delete mCallbacks[i];
+        mCallbacks.RemoveElementAt(i);
+        break;
+      }
+    }
+  }
+}
+
+bool
+CamerasParent::RecvStopCapture(const CaptureEngine& aCapEngine,
+                               const int& capnum)
+{
+  LOG((__PRETTY_FUNCTION__));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> webrtc_runnable =
+    media::NewRunnableFrom([self, aCapEngine, capnum]() -> nsresult {
+      self->StopCapture(aCapEngine, capnum);
+      return NS_OK;
+    });
+  nsresult rv = DispatchToVideoCaptureThread(webrtc_runnable);
+  if (self->IsShuttingDown()) {
+    return NS_SUCCEEDED(rv);
+  } else {
+    if (NS_SUCCEEDED(rv)) {
+      return SendReplySuccess();
+    } else {
+      return SendReplyFailure();
+    }
+  }
+}
+
+void
+CamerasParent::StopIPC()
+{
+  MOZ_ASSERT(!mDestroyed);
+  // Release shared memory now, it's our last chance
+  mShmemPool.Cleanup(this);
+  // We don't want to receive callbacks or anything if we can't
+  // forward them anymore anyway.
+  mChildIsAlive = false;
+  mDestroyed = true;
+}
+
+bool
+CamerasParent::RecvAllDone()
+{
+  LOG((__PRETTY_FUNCTION__));
+  // Don't try to send anything to the child now
+  mChildIsAlive = false;
+  return Send__delete__(this);
+}
+
+void
+CamerasParent::ActorDestroy(ActorDestroyReason aWhy)
+{
+  // No more IPC from here
+  LOG((__PRETTY_FUNCTION__));
+  StopIPC();
+  // Shut down WebRTC (if we're not in full shutdown, else this
+  // will already have happened)
+  StopVideoCapture();
+}
+
+CamerasParent::CamerasParent()
+  : mShmemPool(CaptureEngine::MaxEngine),
+    mThreadMonitor("CamerasParent::mThreadMonitor"),
+    mVideoCaptureThread(nullptr),
+    mChildIsAlive(true),
+    mDestroyed(false),
+    mWebRTCAlive(true)
+{
+  LOG(("CamerasParent: %p", this));
+
+  mPBackgroundThread = NS_GetCurrentThread();
+  MOZ_ASSERT(mPBackgroundThread != nullptr, "GetCurrentThread failed");
+
+  LOG(("Spinning up WebRTC Cameras Thread"));
+
+  RefPtr<CamerasParent> self(this);
+  RefPtr<Runnable> threadStart =
+    media::NewRunnableFrom([self]() -> nsresult {
+      // Register thread shutdown observer
+      nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+      if (NS_WARN_IF(!obs)) {
+        return NS_ERROR_FAILURE;
+      }
+      nsresult rv =
+        obs->AddObserver(self, NS_XPCOM_WILL_SHUTDOWN_OBSERVER_ID, false);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      // Start the thread
+      MonitorAutoLock lock(self->mThreadMonitor);
+      self->mVideoCaptureThread = new base::Thread("VideoCapture");
+      base::Thread::Options options;
+#if defined(_WIN32)
+      options.message_loop_type = MessageLoop::TYPE_MOZILLA_NONMAINUITHREAD;
+#else
+
+      options.message_loop_type = MessageLoop::TYPE_MOZILLA_NONMAINTHREAD;
+#endif
+      if (!self->mVideoCaptureThread->StartWithOptions(options)) {
+        MOZ_CRASH();
+      }
+      self->mThreadMonitor.NotifyAll();
+      return NS_OK;
+    });
+  NS_DispatchToMainThread(threadStart);
+
+  MOZ_COUNT_CTOR(CamerasParent);
+}
+
+CamerasParent::~CamerasParent()
+{
+  LOG(("~CamerasParent: %p", this));
+
+  MOZ_COUNT_DTOR(CamerasParent);
+#ifdef DEBUG
+  // Verify we have shut down the webrtc engines, this is
+  // supposed to happen in ActorDestroy.
+  // That runnable takes a ref to us, so it must have finished
+  // by the time we get here.
+  for (int i = 0; i < CaptureEngine::MaxEngine; i++) {
+    MOZ_ASSERT(!mEngines[i].mEngine);
+  }
+#endif
+}
+
+already_AddRefed<CamerasParent>
+CamerasParent::Create() {
+  mozilla::ipc::AssertIsOnBackgroundThread();
+  RefPtr<CamerasParent> camerasParent = new CamerasParent();
+  return camerasParent.forget();
+}
+
+}
+}
diff --git a/dom/media/systemservices/CamerasParent.h b/dom/media/systemservices/CamerasParent.h
new file mode 100644
index 0000000000..2c18694104
--- /dev/null
+++ b/dom/media/systemservices/CamerasParent.h
@@ -0,0 +1,187 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_CamerasParent_h
+#define mozilla_CamerasParent_h
+
+#include "nsIObserver.h"
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/camera/PCamerasParent.h"
+#include "mozilla/ipc/Shmem.h"
+#include "mozilla/ShmemPool.h"
+#include "mozilla/Atomics.h"
+
+// conflicts with #include of scoped_ptr.h
+#undef FF
+#include "webrtc/common.h"
+// Video Engine
+#include "webrtc/video_engine/include/vie_base.h"
+#include "webrtc/video_engine/include/vie_capture.h"
+#include "webrtc/video_engine/include/vie_render.h"
+#include "CamerasChild.h"
+
+#include "base/thread.h"
+
+namespace mozilla {
+namespace camera {
+
+class CamerasParent;
+
+class CallbackHelper : public webrtc::ExternalRenderer
+{
+public:
+  CallbackHelper(CaptureEngine aCapEng, int aCapId, CamerasParent *aParent)
+    : mCapEngine(aCapEng), mCapturerId(aCapId), mParent(aParent) {};
+
+  // ViEExternalRenderer implementation. These callbacks end up
+  // running on the VideoCapture thread.
+  virtual int FrameSizeChange(unsigned int w, unsigned int h,
+                              unsigned int streams) override;
+  virtual int DeliverFrame(unsigned char* buffer,
+                           size_t size,
+                           uint32_t time_stamp,
+                           int64_t ntp_time,
+                           int64_t render_time,
+                           void *handle) override;
+  virtual int DeliverI420Frame(const webrtc::I420VideoFrame& webrtc_frame) override;
+  virtual bool IsTextureSupported() override { return false; };
+
+  friend CamerasParent;
+
+private:
+  CaptureEngine mCapEngine;
+  int mCapturerId;
+  CamerasParent *mParent;
+};
+
+class EngineHelper
+{
+public:
+  EngineHelper() :
+    mEngine(nullptr), mPtrViEBase(nullptr), mPtrViECapture(nullptr),
+    mPtrViERender(nullptr), mEngineIsRunning(false) {};
+
+  webrtc::VideoEngine *mEngine;
+  webrtc::ViEBase *mPtrViEBase;
+  webrtc::ViECapture *mPtrViECapture;
+  webrtc::ViERender *mPtrViERender;
+
+  // The webrtc code keeps a reference to this one.
+  webrtc::Config mConfig;
+
+  // Engine alive
+  bool mEngineIsRunning;
+};
+
+class InputObserver :  public webrtc::ViEInputObserver
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(InputObserver)
+
+  explicit InputObserver(CamerasParent* aParent)
+    : mParent(aParent) {};
+  virtual void DeviceChange();
+
+  friend CamerasParent;
+
+private:
+  ~InputObserver() {}
+
+  RefPtr<CamerasParent> mParent;
+};
+
+class CamerasParent :  public PCamerasParent,
+                       public nsIObserver
+{
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+public:
+  static already_AddRefed<CamerasParent> Create();
+
+  // Messages received form the child. These run on the IPC/PBackground thread.
+  virtual bool RecvAllocateCaptureDevice(const CaptureEngine&, const nsCString&,
+                                         const nsCString&) override;
+  virtual bool RecvReleaseCaptureDevice(const CaptureEngine&,
+                                        const int&) override;
+  virtual bool RecvNumberOfCaptureDevices(const CaptureEngine&) override;
+  virtual bool RecvNumberOfCapabilities(const CaptureEngine&,
+                                        const nsCString&) override;
+  virtual bool RecvGetCaptureCapability(const CaptureEngine&, const nsCString&,
+                                        const int&) override;
+  virtual bool RecvGetCaptureDevice(const CaptureEngine&, const int&) override;
+  virtual bool RecvStartCapture(const CaptureEngine&, const int&,
+                                const CaptureCapability&) override;
+  virtual bool RecvStopCapture(const CaptureEngine&, const int&) override;
+  virtual bool RecvReleaseFrame(mozilla::ipc::Shmem&&) override;
+  virtual bool RecvAllDone() override;
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+  virtual bool RecvEnsureInitialized(const CaptureEngine&) override;
+
+  nsIThread* GetBackgroundThread() { return mPBackgroundThread; };
+  bool IsShuttingDown() { return !mChildIsAlive
+                              ||  mDestroyed
+                              || !mWebRTCAlive; };
+  ShmemBuffer GetBuffer(size_t aSize);
+
+  // helper to forward to the PBackground thread
+  int DeliverFrameOverIPC(CaptureEngine capEng,
+                          int cap_id,
+                          ShmemBuffer buffer,
+                          unsigned char* altbuffer,
+                          size_t size,
+                          uint32_t time_stamp,
+                          int64_t ntp_time,
+                          int64_t render_time);
+
+
+  CamerasParent();
+
+protected:
+  virtual ~CamerasParent();
+
+  // We use these helpers for shutdown and for the respective IPC commands.
+  void StopCapture(const CaptureEngine& aCapEngine, const int& capnum);
+  int ReleaseCaptureDevice(const CaptureEngine& aCapEngine, const int& capnum);
+
+  bool SetupEngine(CaptureEngine aCapEngine);
+  bool EnsureInitialized(int aEngine);
+  void CloseEngines();
+  void StopIPC();
+  void StopVideoCapture();
+  // Can't take already_AddRefed because it can fail in stupid ways.
+  nsresult DispatchToVideoCaptureThread(Runnable* event);
+
+  EngineHelper mEngines[CaptureEngine::MaxEngine];
+  nsTArray<CallbackHelper*> mCallbacks;
+
+  // image buffers
+  mozilla::ShmemPool mShmemPool;
+
+  // PBackground parent thread
+  nsCOMPtr<nsIThread> mPBackgroundThread;
+
+  // Monitors creation of the thread below
+  Monitor mThreadMonitor;
+
+  // video processing thread - where webrtc.org capturer code runs
+  base::Thread* mVideoCaptureThread;
+
+  // Shutdown handling
+  bool mChildIsAlive;
+  bool mDestroyed;
+  // Above 2 are PBackground only, but this is potentially
+  // read cross-thread.
+  mozilla::Atomic<bool> mWebRTCAlive;
+  nsTArray<RefPtr<InputObserver>> mObservers;
+};
+
+PCamerasParent* CreateCamerasParent();
+
+} // namespace camera
+} // namespace mozilla
+
+#endif  // mozilla_CameraParent_h
diff --git a/dom/media/systemservices/CamerasTypes.h b/dom/media/systemservices/CamerasTypes.h
new file mode 100644
index 0000000000..9ae564e9a2
--- /dev/null
+++ b/dom/media/systemservices/CamerasTypes.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_CamerasTypes_h
+#define mozilla_CamerasTypes_h
+
+#include "ipc/IPCMessageUtils.h"
+
+namespace mozilla {
+
+namespace camera {
+
+enum CaptureEngine : int {
+  InvalidEngine = 0,
+  ScreenEngine,
+  BrowserEngine,
+  WinEngine,
+  AppEngine,
+  CameraEngine,
+  MaxEngine
+};
+
+} // namespace camera
+} // namespace mozilla
+
+namespace IPC {
+template<>
+struct ParamTraits<mozilla::camera::CaptureEngine> :
+    public ContiguousEnumSerializer<mozilla::camera::CaptureEngine,
+                                    mozilla::camera::CaptureEngine::InvalidEngine,
+                                    mozilla::camera::CaptureEngine::MaxEngine>
+{ };
+}
+
+#endif  // mozilla_CamerasTypes_h
diff --git a/dom/media/systemservices/DeviceChangeCallback.h b/dom/media/systemservices/DeviceChangeCallback.h
new file mode 100644
index 0000000000..d153e9cd42
--- /dev/null
+++ b/dom/media/systemservices/DeviceChangeCallback.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_DeviceChangeCallback_h
+#define mozilla_DeviceChangeCallback_h
+
+namespace mozilla {
+
+class DeviceChangeCallback
+{
+public:
+  virtual void OnDeviceChange()
+  {
+    MutexAutoLock lock(mCallbackMutex);
+    for (DeviceChangeCallback* observer : mDeviceChangeCallbackList)
+    {
+      observer->OnDeviceChange();
+    }
+  }
+
+  virtual int AddDeviceChangeCallback(DeviceChangeCallback* aCallback)
+  {
+    MutexAutoLock lock(mCallbackMutex);
+    if (mDeviceChangeCallbackList.IndexOf(aCallback) == mDeviceChangeCallbackList.NoIndex)
+      mDeviceChangeCallbackList.AppendElement(aCallback);
+    return 0;
+  }
+
+  virtual int RemoveDeviceChangeCallback(DeviceChangeCallback* aCallback)
+  {
+    MutexAutoLock lock(mCallbackMutex);
+    return RemoveDeviceChangeCallbackLocked(aCallback);
+  }
+
+  virtual int RemoveDeviceChangeCallbackLocked(DeviceChangeCallback* aCallback)
+  {
+    mCallbackMutex.AssertCurrentThreadOwns();
+    if (mDeviceChangeCallbackList.IndexOf(aCallback) != mDeviceChangeCallbackList.NoIndex)
+      mDeviceChangeCallbackList.RemoveElement(aCallback);
+    return 0;
+  }
+
+  DeviceChangeCallback() : mCallbackMutex("mozilla::media::DeviceChangeCallback::mCallbackMutex")
+  {
+  }
+
+  virtual ~DeviceChangeCallback()
+  {
+  }
+
+protected:
+  nsTArray<DeviceChangeCallback*> mDeviceChangeCallbackList;
+  Mutex mCallbackMutex;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_DeviceChangeCallback_h
diff --git a/dom/media/systemservices/LoadManager.cpp b/dom/media/systemservices/LoadManager.cpp
new file mode 100644
index 0000000000..f0f4f83a7a
--- /dev/null
+++ b/dom/media/systemservices/LoadManager.cpp
@@ -0,0 +1,227 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LoadManager.h"
+#include "LoadMonitor.h"
+#include "nsString.h"
+#include "mozilla/Logging.h"
+#include "prtime.h"
+#include "prinrval.h"
+#include "prsystem.h"
+
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "nsReadableUtils.h"
+#include "nsIObserverService.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/ArrayUtils.h"
+
+// MOZ_LOG=LoadManager:5
+mozilla::LazyLogModule gLoadManagerLog("LoadManager");
+#undef LOG
+#undef LOG_ENABLED
+#define LOG(args) MOZ_LOG(gLoadManagerLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gLoadManagerLog, mozilla::LogLevel::Verbose)
+
+namespace mozilla {
+
+/* static */ StaticRefPtr<LoadManagerSingleton> LoadManagerSingleton::sSingleton;
+
+NS_IMPL_ISUPPORTS(LoadManagerSingleton, nsIObserver)
+
+
+LoadManagerSingleton::LoadManagerSingleton(bool aEncoderOnly,
+                                           int aLoadMeasurementInterval,
+                                           int aAveragingMeasurements,
+                                           float aHighLoadThreshold,
+                                           float aLowLoadThreshold)
+  : mLock("LoadManager"),
+    mCurrentState(webrtc::kLoadNormal),
+    mOveruseActive(false),
+    mLoadSum(0.0f),
+    mLoadSumMeasurements(0),
+    mLoadMeasurementInterval(aLoadMeasurementInterval),
+    mAveragingMeasurements(aAveragingMeasurements),
+    mHighLoadThreshold(aHighLoadThreshold),
+    mLowLoadThreshold(aLowLoadThreshold)
+{
+  LOG(("LoadManager - Initializing (%dms x %d, %f, %f)",
+       mLoadMeasurementInterval, mAveragingMeasurements,
+       mHighLoadThreshold, mLowLoadThreshold));
+  MOZ_ASSERT(mHighLoadThreshold > mLowLoadThreshold);
+  if (!aEncoderOnly) {
+    mLoadMonitor = new LoadMonitor(mLoadMeasurementInterval);
+    mLoadMonitor->Init(mLoadMonitor);
+    mLoadMonitor->SetLoadChangeCallback(this);
+  }
+
+  mLastStateChange = TimeStamp::Now();
+  for (auto &in_state : mTimeInState) {
+    in_state = 0;
+  }
+}
+
+LoadManagerSingleton::~LoadManagerSingleton()
+{
+  LOG(("LoadManager: shutting down LoadMonitor"));
+  MOZ_ASSERT(!mLoadMonitor, "why wasn't the LoadMonitor shut down in xpcom-shutdown?");
+  if (mLoadMonitor) {
+    mLoadMonitor->Shutdown();
+  }
+}
+
+nsresult
+LoadManagerSingleton::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData)
+{
+  NS_ASSERTION(NS_IsMainThread(), "Observer invoked off the main thread");
+  nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+
+  if (!strcmp(aTopic, "xpcom-shutdown")) {
+    obs->RemoveObserver(this, "xpcom-shutdown");
+    {
+      MutexAutoLock lock(mLock);
+      mObservers.Clear();
+    }
+    if (mLoadMonitor) {
+      mLoadMonitor->Shutdown();
+      mLoadMonitor = nullptr;
+    }
+
+    LOG(("Releasing LoadManager singleton and thread"));
+    // Note: won't be released immediately as the Observer has a ref to us
+    sSingleton = nullptr;
+  }
+  return NS_OK;
+}
+
+void
+LoadManagerSingleton::LoadChanged(float aSystemLoad, float aProcesLoad)
+{
+  MutexAutoLock lock(mLock);
+  // Update total load, and total amount of measured seconds.
+  mLoadSum += aSystemLoad;
+  mLoadSumMeasurements++;
+
+  if (mLoadSumMeasurements >= mAveragingMeasurements) {
+    double averagedLoad = mLoadSum / (float)mLoadSumMeasurements;
+
+    webrtc::CPULoadState newState = mCurrentState;
+
+    if (mOveruseActive || averagedLoad > mHighLoadThreshold) {
+      LOG(("LoadManager - LoadStressed"));
+      newState = webrtc::kLoadStressed;
+    } else if (averagedLoad < mLowLoadThreshold) {
+      LOG(("LoadManager - LoadRelaxed"));
+      newState = webrtc::kLoadRelaxed;
+    } else {
+      LOG(("LoadManager - LoadNormal"));
+      newState = webrtc::kLoadNormal;
+    }
+
+    if (newState != mCurrentState) {
+      LoadHasChanged(newState);
+    }
+
+    mLoadSum = 0;
+    mLoadSumMeasurements = 0;
+  }
+}
+
+void
+LoadManagerSingleton::OveruseDetected()
+{
+  LOG(("LoadManager - Overuse Detected"));
+  MutexAutoLock lock(mLock);
+  mOveruseActive = true;
+  if (mCurrentState != webrtc::kLoadStressed) {
+    LoadHasChanged(webrtc::kLoadStressed);
+  }
+}
+
+void
+LoadManagerSingleton::NormalUsage()
+{
+  LOG(("LoadManager - Overuse finished"));
+  MutexAutoLock lock(mLock);
+  mOveruseActive = false;
+}
+
+void
+LoadManagerSingleton::LoadHasChanged(webrtc::CPULoadState aNewState)
+{
+  mLock.AssertCurrentThreadOwns();
+  LOG(("LoadManager - Signaling LoadHasChanged from %d to %d to %d listeners",
+       mCurrentState, aNewState, mObservers.Length()));
+
+  // Record how long we spent in this state for later Telemetry or display
+  TimeStamp now = TimeStamp::Now();
+  mTimeInState[mCurrentState] += (now - mLastStateChange).ToMilliseconds();
+  mLastStateChange = now;
+
+  mCurrentState = aNewState;
+  for (size_t i = 0; i < mObservers.Length(); i++) {
+    mObservers.ElementAt(i)->onLoadStateChanged(mCurrentState);
+  }
+}
+
+void
+LoadManagerSingleton::AddObserver(webrtc::CPULoadStateObserver * aObserver)
+{
+  LOG(("LoadManager - Adding Observer"));
+  MutexAutoLock lock(mLock);
+  mObservers.AppendElement(aObserver);
+}
+
+void
+LoadManagerSingleton::RemoveObserver(webrtc::CPULoadStateObserver * aObserver)
+{
+  LOG(("LoadManager - Removing Observer"));
+  MutexAutoLock lock(mLock);
+  if (!mObservers.RemoveElement(aObserver)) {
+    LOG(("LoadManager - Element to remove not found"));
+  }
+  if (mObservers.Length() == 0) {
+    // Record how long we spent in the final state for later Telemetry or display
+    TimeStamp now = TimeStamp::Now();
+    mTimeInState[mCurrentState] += (now - mLastStateChange).ToMilliseconds();
+
+    float total = 0;
+    for (size_t i = 0; i < MOZ_ARRAY_LENGTH(mTimeInState); i++) {
+      total += mTimeInState[i];
+    }
+    // Don't include short calls; we don't have reasonable load data, and
+    // such short calls rarely reach a stable state.  Keep relatively
+    // short calls separate from longer ones
+    bool log = total > 5*PR_MSEC_PER_SEC;
+    bool small = log && total < 30*PR_MSEC_PER_SEC;
+    if (log) {
+      // Note: We don't care about rounding here; thus total may be < 100
+      Telemetry::Accumulate(small ? Telemetry::WEBRTC_LOAD_STATE_RELAXED_SHORT :
+                            Telemetry::WEBRTC_LOAD_STATE_RELAXED,
+                            (uint32_t) (mTimeInState[webrtc::CPULoadState::kLoadRelaxed]/total * 100));
+      Telemetry::Accumulate(small ? Telemetry::WEBRTC_LOAD_STATE_NORMAL_SHORT :
+                            Telemetry::WEBRTC_LOAD_STATE_NORMAL,
+                            (uint32_t) (mTimeInState[webrtc::CPULoadState::kLoadNormal]/total * 100));
+      Telemetry::Accumulate(small ? Telemetry::WEBRTC_LOAD_STATE_STRESSED_SHORT :
+                            Telemetry::WEBRTC_LOAD_STATE_STRESSED,
+                            (uint32_t) (mTimeInState[webrtc::CPULoadState::kLoadStressed]/total * 100));
+    }
+    for (auto &in_state : mTimeInState) {
+      in_state = 0;
+    }
+
+    if (mLoadMonitor) {
+      // Dance to avoid deadlock on mLock!
+      RefPtr<LoadMonitor> loadMonitor = mLoadMonitor.forget();
+      MutexAutoUnlock unlock(mLock);
+
+      loadMonitor->Shutdown();
+    }
+  }
+}
+
+
+}
diff --git a/dom/media/systemservices/LoadManager.h b/dom/media/systemservices/LoadManager.h
new file mode 100644
index 0000000000..96824a308f
--- /dev/null
+++ b/dom/media/systemservices/LoadManager.h
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _LOADMANAGER_H_
+#define _LOADMANAGER_H_
+
+#include "LoadMonitor.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/TimeStamp.h"
+#include "mozilla/Services.h"
+#include "nsTArray.h"
+#include "nsIObserver.h"
+
+#include "webrtc/common_types.h"
+#include "webrtc/video_engine/include/vie_base.h"
+
+extern mozilla::LazyLogModule gLoadManagerLog;
+
+namespace mozilla {
+
+class LoadManagerSingleton : public LoadNotificationCallback,
+                             public webrtc::CPULoadStateCallbackInvoker,
+                             public webrtc::CpuOveruseObserver,
+                             public nsIObserver
+
+{
+public:
+    static LoadManagerSingleton* Get();
+
+    NS_DECL_THREADSAFE_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+
+    // LoadNotificationCallback interface
+    void LoadChanged(float aSystemLoad, float aProcessLoad) override;
+    // CpuOveruseObserver interface
+    // Called as soon as an overuse is detected.
+    void OveruseDetected() override;
+    // Called periodically when the system is not overused any longer.
+    void NormalUsage() override;
+    // CPULoadStateCallbackInvoker interface
+    void AddObserver(webrtc::CPULoadStateObserver * aObserver) override;
+    void RemoveObserver(webrtc::CPULoadStateObserver * aObserver) override;
+
+private:
+    LoadManagerSingleton(bool aEncoderOnly,
+                         int aLoadMeasurementInterval,
+                         int aAveragingMeasurements,
+                         float aHighLoadThreshold,
+                         float aLowLoadThreshold);
+    ~LoadManagerSingleton();
+
+    void LoadHasChanged(webrtc::CPULoadState aNewState);
+
+    RefPtr<LoadMonitor> mLoadMonitor;
+
+    // This protects access to the mObservers list, the current state, and
+    // pretty much all the other members (below).
+    Mutex mLock;
+    nsTArray<webrtc::CPULoadStateObserver*> mObservers;
+    webrtc::CPULoadState mCurrentState;
+    TimeStamp mLastStateChange;
+    float mTimeInState[static_cast<int>(webrtc::kLoadLast)];
+
+    // Set when overuse was signaled to us, and hasn't been un-signaled yet.
+    bool  mOveruseActive;
+    float mLoadSum;
+    int   mLoadSumMeasurements;
+    // Load measurement settings
+    int mLoadMeasurementInterval;
+    int mAveragingMeasurements;
+    float mHighLoadThreshold;
+    float mLowLoadThreshold;
+
+    static StaticRefPtr<LoadManagerSingleton> sSingleton;
+};
+
+class LoadManager final : public webrtc::CPULoadStateCallbackInvoker,
+                          public webrtc::CpuOveruseObserver
+{
+public:
+    explicit LoadManager(LoadManagerSingleton* aManager)
+        : mManager(aManager)
+    {}
+    ~LoadManager() {}
+
+    void AddObserver(webrtc::CPULoadStateObserver * aObserver) override
+    {
+        mManager->AddObserver(aObserver);
+    }
+    void RemoveObserver(webrtc::CPULoadStateObserver * aObserver) override
+    {
+        mManager->RemoveObserver(aObserver);
+    }
+    void OveruseDetected() override
+    {
+        mManager->OveruseDetected();
+    }
+    void NormalUsage() override
+    {
+        mManager->NormalUsage();
+    }
+
+private:
+    RefPtr<LoadManagerSingleton> mManager;
+};
+
+} //namespace
+
+#endif /* _LOADMANAGER_H_ */
diff --git a/dom/media/systemservices/LoadManagerFactory.cpp b/dom/media/systemservices/LoadManagerFactory.cpp
new file mode 100644
index 0000000000..be22a75fe6
--- /dev/null
+++ b/dom/media/systemservices/LoadManagerFactory.cpp
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LoadManager.h"
+#include "LoadManagerFactory.h"
+#include "MainThreadUtils.h"
+#include "nsIObserverService.h"
+
+#include "mozilla/Preferences.h"
+
+namespace mozilla {
+
+// Assume stored in an nsAutoPtr<>
+LoadManager *
+LoadManagerBuild(void)
+{
+  return new LoadManager(LoadManagerSingleton::Get());
+}
+
+/* static */  LoadManagerSingleton*
+LoadManagerSingleton::Get() {
+  if (!sSingleton) {
+    MOZ_ASSERT(NS_IsMainThread());
+
+    bool loadEncoderOnly =
+      mozilla::Preferences::GetBool("media.navigator.load_adapt.encoder_only", true);
+    int loadMeasurementInterval =
+      mozilla::Preferences::GetInt("media.navigator.load_adapt.measure_interval", 1000);
+    int averagingSeconds =
+      mozilla::Preferences::GetInt("media.navigator.load_adapt.avg_seconds", 3);
+    float highLoadThreshold =
+      mozilla::Preferences::GetFloat("media.navigator.load_adapt.high_load", 0.90f);
+    float lowLoadThreshold =
+      mozilla::Preferences::GetFloat("media.navigator.load_adapt.low_load", 0.40f);
+
+    sSingleton = new LoadManagerSingleton(loadEncoderOnly,
+                                          loadMeasurementInterval,
+                                          averagingSeconds,
+                                          highLoadThreshold,
+                                          lowLoadThreshold);
+
+    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+    if (obs) {
+      obs->AddObserver(sSingleton, "xpcom-shutdown", false);
+    }
+  }
+  return sSingleton;
+}
+
+}; // namespace
diff --git a/dom/media/systemservices/LoadManagerFactory.h b/dom/media/systemservices/LoadManagerFactory.h
new file mode 100644
index 0000000000..4868756f58
--- /dev/null
+++ b/dom/media/systemservices/LoadManagerFactory.h
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _LOADMANAGERFACTORY_H_
+#define _LOADMANAGERFACTORY_H_
+
+namespace mozilla {
+
+class LoadManager;
+
+mozilla::LoadManager* LoadManagerBuild();
+void LoadManagerDestroy(mozilla::LoadManager* aLoadManager);
+
+} //namespace
+
+#endif /* _LOADMANAGERFACTORY_H_ */
diff --git a/dom/media/systemservices/LoadMonitor.cpp b/dom/media/systemservices/LoadMonitor.cpp
new file mode 100644
index 0000000000..7a64c4fb0b
--- /dev/null
+++ b/dom/media/systemservices/LoadMonitor.cpp
@@ -0,0 +1,658 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "LoadMonitor.h"
+#include "LoadManager.h"
+#include "nsString.h"
+#include "mozilla/Logging.h"
+#include "prtime.h"
+#include "prinrval.h"
+#include "prsystem.h"
+#include "prprf.h"
+
+#include "nsString.h"
+#include "nsThreadUtils.h"
+#include "nsReadableUtils.h"
+#include "nsNetUtil.h"
+#include "nsIInputStream.h"
+#include "nsIFile.h"
+#include "nsILineInputStream.h"
+#include "nsIObserverService.h"
+#include "nsIServiceManager.h"
+
+#include "mozilla/TimeStamp.h"
+#include "mozilla/Services.h"
+
+#ifdef XP_UNIX
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <unistd.h>
+#endif
+
+#ifdef XP_MACOSX
+#include <mach/mach_host.h>
+#include <mach/mach_init.h>
+#include <mach/host_info.h>
+#endif
+
+#if defined(__DragonFly__) || defined(__FreeBSD__) \
+ || defined(__NetBSD__) || defined(__OpenBSD__)
+#include <sys/sysctl.h>
+# if defined(__OpenBSD__)
+#define KERN_CP_TIME KERN_CPTIME
+# endif
+#endif
+
+#if defined(__NetBSD__) || defined(__OpenBSD__)
+#include <sys/sched.h>
+#endif
+
+#ifdef XP_WIN
+#include <pdh.h>
+#include <tchar.h>
+#pragma comment(lib, "pdh.lib")
+#endif
+
+// MOZ_LOG=LoadManager:5
+#undef LOG
+#undef LOG_ENABLED
+#define LOG(args) MOZ_LOG(gLoadManagerLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gLoadManagerLog, mozilla::LogLevel::Debug)
+#define LOG_MANY_ENABLED() MOZ_LOG_TEST(gLoadManagerLog, mozilla::LogLevel::Verbose)
+
+namespace mozilla {
+
+NS_IMPL_ISUPPORTS(LoadMonitor, nsIObserver)
+
+LoadMonitor::LoadMonitor(int aLoadUpdateInterval)
+  : mLoadUpdateInterval(aLoadUpdateInterval),
+    mLock("LoadMonitor.mLock"),
+    mCondVar(mLock, "LoadMonitor.mCondVar"),
+    mShutdownPending(false),
+    mLoadInfoThread(nullptr),
+    mSystemLoad(0.0f),
+    mProcessLoad(0.0f),
+    mLoadNotificationCallback(nullptr)
+{
+}
+
+LoadMonitor::~LoadMonitor()
+{
+  Shutdown();
+}
+
+NS_IMETHODIMP
+LoadMonitor::Observe(nsISupports* /* aSubject */,
+                     const char*  aTopic,
+                     const char16_t* /* aData */)
+{
+  MOZ_ASSERT(NS_IsMainThread(), "Wrong thread!");
+  MOZ_ASSERT(!strcmp("xpcom-shutdown-threads", aTopic), "Bad topic!");
+  Shutdown();
+  return NS_OK;
+}
+
+class LoadMonitorAddObserver : public Runnable
+{
+public:
+  explicit LoadMonitorAddObserver(RefPtr<LoadMonitor> loadMonitor)
+  {
+    mLoadMonitor = loadMonitor;
+  }
+
+  NS_IMETHOD Run() override
+  {
+    nsCOMPtr<nsIObserverService> observerService =
+        mozilla::services::GetObserverService();
+    if (!observerService)
+      return NS_ERROR_FAILURE;
+
+    nsresult rv = observerService->AddObserver(mLoadMonitor, "xpcom-shutdown-threads", false);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return NS_OK;
+  }
+
+private:
+  RefPtr<LoadMonitor> mLoadMonitor;
+};
+
+class LoadMonitorRemoveObserver : public Runnable
+{
+public:
+  explicit LoadMonitorRemoveObserver(RefPtr<LoadMonitor> loadMonitor)
+  {
+    mLoadMonitor = loadMonitor;
+  }
+
+  NS_IMETHOD Run() override
+  {
+    // remove xpcom shutdown observer
+    nsCOMPtr<nsIObserverService> observerService =
+      mozilla::services::GetObserverService();
+
+    if (observerService)
+      observerService->RemoveObserver(mLoadMonitor, "xpcom-shutdown-threads");
+
+    return NS_OK;
+  }
+
+private:
+  RefPtr<LoadMonitor> mLoadMonitor;
+};
+
+void LoadMonitor::Shutdown()
+{
+  if (mLoadInfoThread) {
+    {
+      MutexAutoLock lock(mLock);
+      LOG(("LoadMonitor: shutting down"));
+      mShutdownPending = true;
+      mCondVar.Notify();
+    }
+
+    // Note: can't just call ->Shutdown() from here; that spins the event
+    // loop here, causing re-entrancy issues if we're invoked from cycle
+    // collection.  Argh.
+    mLoadInfoThread = nullptr;
+
+    RefPtr<LoadMonitorRemoveObserver> remObsRunner = new LoadMonitorRemoveObserver(this);
+    if (!NS_IsMainThread()) {
+      NS_DispatchToMainThread(remObsRunner);
+    } else {
+      remObsRunner->Run();
+    }
+  }
+}
+
+#ifdef XP_WIN
+static LPCTSTR TotalCounterPath = _T("\\Processor(_Total)\\% Processor Time");
+
+class WinProcMon
+{
+public:
+  WinProcMon():
+    mQuery(0), mCounter(0) {};
+  ~WinProcMon();
+  nsresult Init();
+  nsresult QuerySystemLoad(float* load_percent);
+  static const uint64_t TicksPerSec = 10000000; //100nsec tick (10MHz)
+private:
+  PDH_HQUERY mQuery;
+  PDH_HCOUNTER mCounter;
+};
+
+WinProcMon::~WinProcMon()
+{
+  if (mQuery != 0) {
+    PdhCloseQuery(mQuery);
+    mQuery = 0;
+  }
+}
+
+nsresult
+WinProcMon::Init()
+{
+  PDH_HQUERY query;
+  PDH_HCOUNTER counter;
+
+  // Get a query handle to the Performance Data Helper
+  PDH_STATUS status = PdhOpenQuery(
+                        NULL,      // No log file name: use real-time source
+                        0,         // zero out user data token: unsued
+                        &query);
+
+  if (status != ERROR_SUCCESS) {
+    LOG(("PdhOpenQuery error = %X", status));
+    return NS_ERROR_FAILURE;
+  }
+
+  // Add a pre-defined high performance counter to the query.
+  // This one is for the total CPU usage.
+  status = PdhAddCounter(query, TotalCounterPath, 0, &counter);
+
+  if (status != ERROR_SUCCESS) {
+    PdhCloseQuery(query);
+    LOG(("PdhAddCounter (_Total) error = %X", status));
+    return NS_ERROR_FAILURE;
+  }
+
+  // Need to make an initial query call to set up data capture.
+  status = PdhCollectQueryData(query);
+
+  if (status != ERROR_SUCCESS) {
+    PdhCloseQuery(query);
+    LOG(("PdhCollectQueryData (init) error = %X", status));
+    return NS_ERROR_FAILURE;
+  }
+
+  mQuery = query;
+  mCounter = counter;
+  return NS_OK;
+}
+
+nsresult WinProcMon::QuerySystemLoad(float* load_percent)
+{
+  *load_percent = 0;
+
+  if (mQuery == 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  // Update all counters associated with this query object.
+  PDH_STATUS status = PdhCollectQueryData(mQuery);
+
+  if (status != ERROR_SUCCESS) {
+    LOG(("PdhCollectQueryData error = %X", status));
+    return NS_ERROR_FAILURE;
+  }
+
+  PDH_FMT_COUNTERVALUE counter;
+  // maximum is 100% regardless of CPU core count.
+  status = PdhGetFormattedCounterValue(
+               mCounter,
+               PDH_FMT_DOUBLE,
+               (LPDWORD)NULL,
+               &counter);
+
+  if (ERROR_SUCCESS != status ||
+      // There are multiple success return values.
+      !IsSuccessSeverity(counter.CStatus)) {
+    LOG(("PdhGetFormattedCounterValue error"));
+    return NS_ERROR_FAILURE;
+  }
+
+  // The result is a percent value, reduce to match expected scale.
+  *load_percent = (float)(counter.doubleValue / 100.0f);
+  return NS_OK;
+}
+#endif
+
+// Use a non-generic class name, because otherwise we can get name collisions
+// with other classes in the codebase.  The normal way of dealing with that is
+// to put the class in an anonymous namespace, but this class is used as a
+// member of RTCLoadInfo, which can't be in the anonymous namespace, so it also
+// can't be in an anonymous namespace: gcc warns about that setup and this
+// directory is fail-on-warnings.
+class RTCLoadStats
+{
+public:
+  RTCLoadStats() :
+    mPrevTotalTimes(0),
+    mPrevCpuTimes(0),
+    mPrevLoad(0) {};
+
+  double GetLoad() { return (double)mPrevLoad; };
+
+  uint64_t mPrevTotalTimes;
+  uint64_t mPrevCpuTimes;
+  float mPrevLoad;               // Previous load value.
+};
+
+// Use a non-generic class name, because otherwise we can get name collisions
+// with other classes in the codebase.  The normal way of dealing with that is
+// to put the class in an anonymous namespace, but this class is used as a
+// member of LoadInfoCollectRunner, which can't be in the anonymous namespace,
+// so it also can't be in an anonymous namespace: gcc warns about that setup
+// and this directory is fail-on-warnings.
+class RTCLoadInfo final
+{
+private:
+  ~RTCLoadInfo() {}
+
+public:
+  NS_INLINE_DECL_REFCOUNTING(RTCLoadInfo)
+
+  RTCLoadInfo(): mLoadUpdateInterval(0) {};
+  nsresult Init(int aLoadUpdateInterval);
+  double GetSystemLoad() { return mSystemLoad.GetLoad(); };
+  double GetProcessLoad() { return mProcessLoad.GetLoad(); };
+  nsresult UpdateSystemLoad();
+  nsresult UpdateProcessLoad();
+
+private:
+  void UpdateCpuLoad(uint64_t ticks_per_interval,
+                     uint64_t current_total_times,
+                     uint64_t current_cpu_times,
+                     RTCLoadStats* loadStat);
+#ifdef XP_WIN
+  WinProcMon mSysMon;
+  HANDLE mProcHandle;
+  int mNumProcessors;
+#endif
+  RTCLoadStats mSystemLoad;
+  RTCLoadStats mProcessLoad;
+  uint64_t mTicksPerInterval;
+  int mLoadUpdateInterval;
+};
+
+nsresult RTCLoadInfo::Init(int aLoadUpdateInterval)
+{
+  mLoadUpdateInterval = aLoadUpdateInterval;
+#ifdef XP_WIN
+  mTicksPerInterval = (WinProcMon::TicksPerSec /*Hz*/
+                       * mLoadUpdateInterval /*msec*/) / 1000 ;
+  mNumProcessors = PR_GetNumberOfProcessors();
+  mProcHandle = GetCurrentProcess();
+  return mSysMon.Init();
+#else
+  mTicksPerInterval = (sysconf(_SC_CLK_TCK) * mLoadUpdateInterval) / 1000;
+  return NS_OK;
+#endif
+}
+
+void RTCLoadInfo::UpdateCpuLoad(uint64_t ticks_per_interval,
+                                uint64_t current_total_times,
+                                uint64_t current_cpu_times,
+                                RTCLoadStats *loadStat) {
+  // Check if we get an inconsistent number of ticks.
+  if (((current_total_times - loadStat->mPrevTotalTimes)
+       > (ticks_per_interval * 10))
+      || current_total_times < loadStat->mPrevTotalTimes
+      || current_cpu_times < loadStat->mPrevCpuTimes) {
+    // Bug at least on the Nexus 4 and Galaxy S4
+    // https://code.google.com/p/android/issues/detail?id=41630
+    // We do need to update our previous times, or we can get stuck
+    // when there is a blip upwards and then we get a bunch of consecutive
+    // lower times. Just skip the load calculation.
+    LOG(("Inconsistent time values are passed. ignored"));
+    // Try to recover next tick
+    loadStat->mPrevTotalTimes = current_total_times;
+    loadStat->mPrevCpuTimes = current_cpu_times;
+    return;
+  }
+
+  const uint64_t cpu_diff = current_cpu_times - loadStat->mPrevCpuTimes;
+  const uint64_t total_diff = current_total_times - loadStat->mPrevTotalTimes;
+  if (total_diff > 0) {
+#ifdef XP_WIN
+    float result =  (float)cpu_diff / (float)total_diff/ (float)mNumProcessors;
+#else
+    float result =  (float)cpu_diff / (float)total_diff;
+#endif
+    loadStat->mPrevLoad = result;
+  }
+  loadStat->mPrevTotalTimes = current_total_times;
+  loadStat->mPrevCpuTimes = current_cpu_times;
+}
+
+nsresult RTCLoadInfo::UpdateSystemLoad()
+{
+#if defined(LINUX) || defined(ANDROID)
+  nsCOMPtr<nsIFile> procStatFile = do_CreateInstance(NS_LOCAL_FILE_CONTRACTID);
+  procStatFile->InitWithPath(NS_LITERAL_STRING("/proc/stat"));
+
+  nsCOMPtr<nsIInputStream> fileInputStream;
+  nsresult rv = NS_NewLocalFileInputStream(getter_AddRefs(fileInputStream),
+                                           procStatFile);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsILineInputStream> lineInputStream = do_QueryInterface(fileInputStream, &rv);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsAutoCString buffer;
+  bool isMore = true;
+  lineInputStream->ReadLine(buffer, &isMore);
+
+  uint64_t user;
+  uint64_t nice;
+  uint64_t system;
+  uint64_t idle;
+  if (PR_sscanf(buffer.get(), "cpu %llu %llu %llu %llu",
+                &user, &nice,
+                &system, &idle) != 4) {
+    LOG(("Error parsing /proc/stat"));
+    return NS_ERROR_FAILURE;
+  }
+
+  const uint64_t cpu_times = nice + system + user;
+  const uint64_t total_times = cpu_times + idle;
+
+  UpdateCpuLoad(mTicksPerInterval,
+                total_times,
+                cpu_times,
+                &mSystemLoad);
+  return NS_OK;
+#elif defined(XP_MACOSX)
+  mach_msg_type_number_t info_cnt = HOST_CPU_LOAD_INFO_COUNT;
+  host_cpu_load_info_data_t load_info;
+  kern_return_t rv = host_statistics(mach_host_self(), HOST_CPU_LOAD_INFO,
+                                     (host_info_t)(&load_info), &info_cnt);
+
+  if (rv != KERN_SUCCESS || info_cnt != HOST_CPU_LOAD_INFO_COUNT) {
+    LOG(("Error from mach/host_statistics call"));
+    return NS_ERROR_FAILURE;
+  }
+
+  const uint64_t cpu_times = load_info.cpu_ticks[CPU_STATE_NICE]
+                           + load_info.cpu_ticks[CPU_STATE_SYSTEM]
+                           + load_info.cpu_ticks[CPU_STATE_USER];
+  const uint64_t total_times = cpu_times + load_info.cpu_ticks[CPU_STATE_IDLE];
+
+  UpdateCpuLoad(mTicksPerInterval,
+                total_times,
+                cpu_times,
+                &mSystemLoad);
+  return NS_OK;
+#elif defined(__DragonFly__) || defined(__FreeBSD__) \
+   || defined(__NetBSD__) || defined(__OpenBSD__)
+#if defined(__NetBSD__)
+  uint64_t cp_time[CPUSTATES];
+#else
+  long cp_time[CPUSTATES];
+#endif // __NetBSD__
+  size_t sz = sizeof(cp_time);
+#ifdef KERN_CP_TIME
+  int mib[] = {
+    CTL_KERN,
+    KERN_CP_TIME,
+  };
+  u_int miblen = sizeof(mib) / sizeof(mib[0]);
+  if (sysctl(mib, miblen, &cp_time, &sz, nullptr, 0)) {
+#else
+  if (sysctlbyname("kern.cp_time", &cp_time, &sz, nullptr, 0)) {
+#endif // KERN_CP_TIME
+    LOG(("sysctl kern.cp_time failed"));
+    return NS_ERROR_FAILURE;
+  }
+
+  const uint64_t cpu_times = cp_time[CP_NICE]
+                           + cp_time[CP_SYS]
+                           + cp_time[CP_INTR]
+                           + cp_time[CP_USER];
+  const uint64_t total_times = cpu_times + cp_time[CP_IDLE];
+
+  UpdateCpuLoad(mTicksPerInterval,
+                total_times,
+                cpu_times,
+                &mSystemLoad);
+  return NS_OK;
+#elif defined(XP_WIN)
+  float load;
+  nsresult rv = mSysMon.QuerySystemLoad(&load);
+
+  if (rv == NS_OK) {
+    mSystemLoad.mPrevLoad = load;
+  }
+
+  return rv;
+#else
+  // Not implemented
+  return NS_OK;
+#endif
+}
+
+nsresult RTCLoadInfo::UpdateProcessLoad() {
+#if defined(XP_UNIX)
+  struct timeval tv;
+  gettimeofday(&tv, nullptr);
+  const uint64_t total_times = tv.tv_sec * PR_USEC_PER_SEC + tv.tv_usec;
+
+  rusage usage;
+  if (getrusage(RUSAGE_SELF, &usage) < 0) {
+    LOG(("getrusage failed"));
+    return NS_ERROR_FAILURE;
+  }
+
+  const uint64_t cpu_times =
+      (usage.ru_utime.tv_sec + usage.ru_stime.tv_sec) * PR_USEC_PER_SEC +
+       usage.ru_utime.tv_usec + usage.ru_stime.tv_usec;
+
+  UpdateCpuLoad(PR_USEC_PER_MSEC * mLoadUpdateInterval,
+                total_times,
+                cpu_times,
+                &mProcessLoad);
+#elif defined(XP_WIN)
+  FILETIME clk_time, sys_time, user_time;
+  uint64_t total_times, cpu_times;
+
+  GetSystemTimeAsFileTime(&clk_time);
+  total_times = (((uint64_t)clk_time.dwHighDateTime) << 32)
+                + (uint64_t)clk_time.dwLowDateTime;
+  BOOL ok = GetProcessTimes(mProcHandle, &clk_time, &clk_time, &sys_time, &user_time);
+
+  if (ok == 0) {
+    return NS_ERROR_FAILURE;
+  }
+
+  cpu_times = (((uint64_t)sys_time.dwHighDateTime
+                + (uint64_t)user_time.dwHighDateTime) << 32)
+              + (uint64_t)sys_time.dwLowDateTime
+              + (uint64_t)user_time.dwLowDateTime;
+
+  UpdateCpuLoad(mTicksPerInterval,
+                total_times,
+                cpu_times,
+                &mProcessLoad);
+#endif
+  return NS_OK;
+}
+
+// Note: This class can't be in the anonymous namespace, because then we can't
+// declare it as a friend of LoadMonitor.
+class LoadInfoCollectRunner : public Runnable
+{
+public:
+  LoadInfoCollectRunner(RefPtr<LoadMonitor> loadMonitor,
+                        RefPtr<RTCLoadInfo> loadInfo,
+                        nsIThread *loadInfoThread)
+    : mThread(loadInfoThread),
+      mLoadUpdateInterval(loadMonitor->mLoadUpdateInterval),
+      mLoadNoiseCounter(0)
+  {
+    mLoadMonitor = loadMonitor;
+    mLoadInfo = loadInfo;
+  }
+
+  NS_IMETHOD Run() override
+  {
+    if (NS_IsMainThread()) {
+      if (mThread) {
+        // Don't leak threads!
+        mThread->Shutdown(); // can't Shutdown from the thread itself, darn
+        // Don't null out mThread!
+        // See bug 999104.  We must hold a ref to the thread across Dispatch()
+        // since the internal mThread ref could be released while processing
+        // the Dispatch(), and Dispatch/PutEvent itself doesn't hold a ref; it
+        // assumes the caller does.
+      }
+      return NS_OK;
+    }
+
+    MutexAutoLock lock(mLoadMonitor->mLock);
+    while (!mLoadMonitor->mShutdownPending) {
+      mLoadInfo->UpdateSystemLoad();
+      mLoadInfo->UpdateProcessLoad();
+      float sysLoad = mLoadInfo->GetSystemLoad();
+      float procLoad = mLoadInfo->GetProcessLoad();
+
+      if ((++mLoadNoiseCounter % (LOG_MANY_ENABLED() ? 1 : 10)) == 0) {
+        LOG(("System Load: %f Process Load: %f", sysLoad, procLoad));
+        mLoadNoiseCounter = 0;
+      }
+      mLoadMonitor->SetSystemLoad(sysLoad);
+      mLoadMonitor->SetProcessLoad(procLoad);
+      mLoadMonitor->FireCallbacks();
+
+      mLoadMonitor->mCondVar.Wait(PR_MillisecondsToInterval(mLoadUpdateInterval));
+    }
+    // ok, we need to exit safely and can't shut ourselves down (DARN)
+    NS_DispatchToMainThread(this);
+    return NS_OK;
+  }
+
+private:
+  nsCOMPtr<nsIThread> mThread;
+  RefPtr<RTCLoadInfo> mLoadInfo;
+  RefPtr<LoadMonitor> mLoadMonitor;
+  int mLoadUpdateInterval;
+  int mLoadNoiseCounter;
+};
+
+void
+LoadMonitor::SetProcessLoad(float load) {
+  mLock.AssertCurrentThreadOwns();
+  mProcessLoad = load;
+}
+
+void
+LoadMonitor::SetSystemLoad(float load) {
+  mLock.AssertCurrentThreadOwns();
+  mSystemLoad = load;
+}
+
+float
+LoadMonitor::GetProcessLoad() {
+  MutexAutoLock lock(mLock);
+  float load = mProcessLoad;
+  return load;
+}
+
+void
+LoadMonitor::FireCallbacks() {
+  if (mLoadNotificationCallback) {
+    mLoadNotificationCallback->LoadChanged(mSystemLoad, mProcessLoad);
+  }
+}
+
+float
+LoadMonitor::GetSystemLoad() {
+  MutexAutoLock lock(mLock);
+  float load = mSystemLoad;
+  return load;
+}
+
+nsresult
+LoadMonitor::Init(RefPtr<LoadMonitor> &self)
+{
+  LOG(("Initializing LoadMonitor"));
+
+  RefPtr<RTCLoadInfo> load_info = new RTCLoadInfo();
+  nsresult rv = load_info->Init(mLoadUpdateInterval);
+
+  if (NS_FAILED(rv)) {
+    LOG(("RTCLoadInfo::Init error"));
+    return rv;
+  }
+
+  RefPtr<LoadMonitorAddObserver> addObsRunner = new LoadMonitorAddObserver(self);
+  NS_DispatchToMainThread(addObsRunner);
+
+  NS_NewNamedThread("Sys Load Info", getter_AddRefs(mLoadInfoThread));
+
+  RefPtr<LoadInfoCollectRunner> runner =
+    new LoadInfoCollectRunner(self, load_info, mLoadInfoThread);
+  mLoadInfoThread->Dispatch(runner, NS_DISPATCH_NORMAL);
+
+  return NS_OK;
+}
+
+void
+LoadMonitor::SetLoadChangeCallback(LoadNotificationCallback* aCallback)
+{
+  mLoadNotificationCallback = aCallback;
+}
+
+}
diff --git a/dom/media/systemservices/LoadMonitor.h b/dom/media/systemservices/LoadMonitor.h
new file mode 100644
index 0000000000..3731b97dc5
--- /dev/null
+++ b/dom/media/systemservices/LoadMonitor.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _LOADMONITOR_H_
+#define _LOADMONITOR_H_
+
+#include "mozilla/Mutex.h"
+#include "mozilla/CondVar.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Atomics.h"
+#include "nsCOMPtr.h"
+#include "nsIThread.h"
+#include "nsIObserver.h"
+
+namespace mozilla {
+class LoadInfoCollectRunner;
+
+class LoadNotificationCallback
+{
+public:
+    virtual void LoadChanged(float aSystemLoad, float aProcessLoad) = 0;
+};
+
+class LoadMonitor final : public nsIObserver
+{
+public:
+    NS_DECL_THREADSAFE_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+
+    explicit LoadMonitor(int aLoadUpdateInterval);
+
+    nsresult Init(RefPtr<LoadMonitor> &self);
+    void SetLoadChangeCallback(LoadNotificationCallback* aCallback);
+    void Shutdown();
+    float GetSystemLoad();
+    float GetProcessLoad();
+
+    friend class LoadInfoCollectRunner;
+
+private:
+    ~LoadMonitor();
+
+    void SetProcessLoad(float load);
+    void SetSystemLoad(float load);
+    void FireCallbacks();
+
+    int                  mLoadUpdateInterval;
+    mozilla::Mutex       mLock;
+    mozilla::CondVar     mCondVar;
+    bool                 mShutdownPending;
+    nsCOMPtr<nsIThread>  mLoadInfoThread;
+    float                mSystemLoad;
+    float                mProcessLoad;
+    LoadNotificationCallback* mLoadNotificationCallback;
+};
+
+} //namespace
+
+#endif /* _LOADMONITOR_H_ */
diff --git a/dom/media/systemservices/MediaChild.cpp b/dom/media/systemservices/MediaChild.cpp
new file mode 100644
index 0000000000..327ea3c4ad
--- /dev/null
+++ b/dom/media/systemservices/MediaChild.cpp
@@ -0,0 +1,115 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaChild.h"
+#include "MediaParent.h"
+
+#include "nsGlobalWindow.h"
+#include "mozilla/MediaManager.h"
+#include "mozilla/Logging.h"
+#include "nsQueryObject.h"
+
+#undef LOG
+mozilla::LazyLogModule gMediaChildLog("MediaChild");
+#define LOG(args) MOZ_LOG(gMediaChildLog, mozilla::LogLevel::Debug, args)
+
+namespace mozilla {
+namespace media {
+
+already_AddRefed<Pledge<nsCString>>
+GetOriginKey(const nsCString& aOrigin, bool aPrivateBrowsing, bool aPersist)
+{
+  RefPtr<MediaManager> mgr = MediaManager::GetInstance();
+  MOZ_ASSERT(mgr);
+
+  RefPtr<Pledge<nsCString>> p = new Pledge<nsCString>();
+  uint32_t id = mgr->mGetOriginKeyPledges.Append(*p);
+
+  if (XRE_GetProcessType() == GeckoProcessType_Default) {
+    mgr->GetNonE10sParent()->RecvGetOriginKey(id, aOrigin, aPrivateBrowsing,
+                                              aPersist);
+  } else {
+    Child::Get()->SendGetOriginKey(id, aOrigin, aPrivateBrowsing, aPersist);
+  }
+  return p.forget();
+}
+
+void
+SanitizeOriginKeys(const uint64_t& aSinceWhen, bool aOnlyPrivateBrowsing)
+{
+  LOG(("SanitizeOriginKeys since %llu %s", aSinceWhen,
+       (aOnlyPrivateBrowsing? "in Private Browsing." : ".")));
+
+  if (XRE_GetProcessType() == GeckoProcessType_Default) {
+    // Avoid opening MediaManager in this case, since this is called by
+    // sanitize.js when cookies are cleared, which can happen on startup.
+    RefPtr<Parent<NonE10s>> tmpParent = new Parent<NonE10s>();
+    tmpParent->RecvSanitizeOriginKeys(aSinceWhen, aOnlyPrivateBrowsing);
+  } else {
+    Child::Get()->SendSanitizeOriginKeys(aSinceWhen, aOnlyPrivateBrowsing);
+  }
+}
+
+static Child* sChild;
+
+Child* Child::Get()
+{
+  MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Content);
+  MOZ_ASSERT(NS_IsMainThread());
+  if (!sChild) {
+    sChild = static_cast<Child*>(dom::ContentChild::GetSingleton()->SendPMediaConstructor());
+  }
+  return sChild;
+}
+
+Child::Child()
+  : mActorDestroyed(false)
+{
+  LOG(("media::Child: %p", this));
+  MOZ_COUNT_CTOR(Child);
+}
+
+Child::~Child()
+{
+  LOG(("~media::Child: %p", this));
+  sChild = nullptr;
+  MOZ_COUNT_DTOR(Child);
+}
+
+void Child::ActorDestroy(ActorDestroyReason aWhy)
+{
+  mActorDestroyed = true;
+}
+
+bool
+Child::RecvGetOriginKeyResponse(const uint32_t& aRequestId, const nsCString& aKey)
+{
+  RefPtr<MediaManager> mgr = MediaManager::GetInstance();
+  if (!mgr) {
+    return false;
+  }
+  RefPtr<Pledge<nsCString>> pledge = mgr->mGetOriginKeyPledges.Remove(aRequestId);
+  if (pledge) {
+    pledge->Resolve(aKey);
+  }
+  return true;
+}
+
+PMediaChild*
+AllocPMediaChild()
+{
+  return new Child();
+}
+
+bool
+DeallocPMediaChild(media::PMediaChild *aActor)
+{
+  delete static_cast<Child*>(aActor);
+  return true;
+}
+
+} // namespace media
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaChild.h b/dom/media/systemservices/MediaChild.h
new file mode 100644
index 0000000000..b013c4a5f5
--- /dev/null
+++ b/dom/media/systemservices/MediaChild.h
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MediaChild_h
+#define mozilla_MediaChild_h
+
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/media/PMediaChild.h"
+#include "mozilla/media/PMediaParent.h"
+#include "MediaUtils.h"
+
+namespace mozilla {
+namespace media {
+
+// media::Child implements proxying to the chrome process for some media-related
+// functions, for the moment just:
+//
+// GetOriginKey() - get a cookie-like persisted unique key for a given origin.
+// SanitizeOriginKeys() - reset persisted unique keys.
+
+// GetOriginKey and SanitizeOriginKeys are asynchronous APIs that return pledges
+// (promise-like objects) with the future value. Use pledge.Then(func) to access.
+
+already_AddRefed<Pledge<nsCString>>
+GetOriginKey(const nsCString& aOrigin, bool aPrivateBrowsing, bool aPersist);
+
+void
+SanitizeOriginKeys(const uint64_t& aSinceWhen, bool aOnlyPrivateBrowsing);
+
+class Child : public PMediaChild
+{
+public:
+  static Child* Get();
+
+  Child();
+
+  bool RecvGetOriginKeyResponse(const uint32_t& aRequestId, const nsCString& aKey) override;
+
+  void ActorDestroy(ActorDestroyReason aWhy) override;
+  virtual ~Child();
+private:
+
+  bool mActorDestroyed;
+};
+
+PMediaChild* AllocPMediaChild();
+bool DeallocPMediaChild(PMediaChild *aActor);
+
+} // namespace media
+} // namespace mozilla
+
+#endif  // mozilla_MediaChild_h
diff --git a/dom/media/systemservices/MediaParent.cpp b/dom/media/systemservices/MediaParent.cpp
new file mode 100644
index 0000000000..109a44a28a
--- /dev/null
+++ b/dom/media/systemservices/MediaParent.cpp
@@ -0,0 +1,516 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaParent.h"
+
+#include "mozilla/Base64.h"
+#include <mozilla/StaticMutex.h>
+
+#include "MediaUtils.h"
+#include "MediaEngine.h"
+#include "VideoUtils.h"
+#include "nsAutoPtr.h"
+#include "nsThreadUtils.h"
+#include "nsNetCID.h"
+#include "nsNetUtil.h"
+#include "nsIInputStream.h"
+#include "nsILineInputStream.h"
+#include "nsIOutputStream.h"
+#include "nsISafeOutputStream.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsISupportsImpl.h"
+#include "mozilla/Logging.h"
+
+#undef LOG
+mozilla::LazyLogModule gMediaParentLog("MediaParent");
+#define LOG(args) MOZ_LOG(gMediaParentLog, mozilla::LogLevel::Debug, args)
+
+// A file in the profile dir is used to persist mOriginKeys used to anonymize
+// deviceIds to be unique per origin, to avoid them being supercookies.
+
+#define ORIGINKEYS_FILE "enumerate_devices.txt"
+#define ORIGINKEYS_VERSION "1"
+
+namespace mozilla {
+namespace media {
+
+static OriginKeyStore* sOriginKeyStore = nullptr;
+
+class OriginKeyStore : public nsISupports
+{
+  NS_DECL_THREADSAFE_ISUPPORTS
+  class OriginKey
+  {
+  public:
+    static const size_t DecodedLength = 18;
+    static const size_t EncodedLength = DecodedLength * 4 / 3;
+
+    explicit OriginKey(const nsACString& aKey, int64_t aSecondsStamp = 0) // 0 = temporal
+    : mKey(aKey)
+    , mSecondsStamp(aSecondsStamp) {}
+
+    nsCString mKey; // Base64 encoded.
+    int64_t mSecondsStamp;
+  };
+
+  class OriginKeysTable
+  {
+  public:
+    OriginKeysTable() : mPersistCount(0) {}
+
+    nsresult
+    GetOriginKey(const nsACString& aOrigin, nsCString& aResult, bool aPersist = false)
+    {
+      OriginKey* key;
+      if (!mKeys.Get(aOrigin, &key)) {
+        nsCString salt; // Make a new one
+        nsresult rv = GenerateRandomName(salt, key->EncodedLength);
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          return rv;
+        }
+        key = new OriginKey(salt);
+        mKeys.Put(aOrigin, key);
+      }
+      if (aPersist && !key->mSecondsStamp) {
+        key->mSecondsStamp = PR_Now() / PR_USEC_PER_SEC;
+        mPersistCount++;
+      }
+      aResult = key->mKey;
+      return NS_OK;
+    }
+
+    void Clear(int64_t aSinceWhen)
+    {
+      // Avoid int64_t* <-> void* casting offset
+      OriginKey since(nsCString(), aSinceWhen  / PR_USEC_PER_SEC);
+      for (auto iter = mKeys.Iter(); !iter.Done(); iter.Next()) {
+        nsAutoPtr<OriginKey>& originKey = iter.Data();
+        LOG((((originKey->mSecondsStamp >= since.mSecondsStamp)?
+              "%s: REMOVE %lld >= %lld" :
+              "%s: KEEP   %lld < %lld"),
+              __FUNCTION__, originKey->mSecondsStamp, since.mSecondsStamp));
+
+        if (originKey->mSecondsStamp >= since.mSecondsStamp) {
+          iter.Remove();
+        }
+      }
+      mPersistCount = 0;
+    }
+
+  protected:
+    nsClassHashtable<nsCStringHashKey, OriginKey> mKeys;
+    size_t mPersistCount;
+  };
+
+  class OriginKeysLoader : public OriginKeysTable
+  {
+  public:
+    OriginKeysLoader() {}
+
+    nsresult
+    GetOriginKey(const nsACString& aOrigin, nsCString& aResult, bool aPersist)
+    {
+      auto before = mPersistCount;
+      OriginKeysTable::GetOriginKey(aOrigin, aResult, aPersist);
+      if (mPersistCount != before) {
+        Save();
+      }
+      return NS_OK;
+    }
+
+    already_AddRefed<nsIFile>
+    GetFile()
+    {
+      MOZ_ASSERT(mProfileDir);
+      nsCOMPtr<nsIFile> file;
+      nsresult rv = mProfileDir->Clone(getter_AddRefs(file));
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return nullptr;
+      }
+      file->Append(NS_LITERAL_STRING(ORIGINKEYS_FILE));
+      return file.forget();
+    }
+
+    // Format of file is key secondsstamp origin (first line is version #):
+    //
+    // 1
+    // rOMAAbFujNwKyIpj4RJ3Wt5Q 1424733961 http://fiddle.jshell.net
+    // rOMAAbFujNwKyIpj4RJ3Wt5Q 1424734841 http://mozilla.github.io
+    // etc.
+
+    nsresult Read()
+    {
+      nsCOMPtr<nsIFile> file = GetFile();
+      if (NS_WARN_IF(!file)) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      bool exists;
+      nsresult rv = file->Exists(&exists);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      if (!exists) {
+        return NS_OK;
+      }
+
+      nsCOMPtr<nsIInputStream> stream;
+      rv = NS_NewLocalFileInputStream(getter_AddRefs(stream), file);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      nsCOMPtr<nsILineInputStream> i = do_QueryInterface(stream);
+      MOZ_ASSERT(i);
+      MOZ_ASSERT(!mPersistCount);
+
+      nsCString line;
+      bool hasMoreLines;
+      rv = i->ReadLine(line, &hasMoreLines);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      if (!line.EqualsLiteral(ORIGINKEYS_VERSION)) {
+        // If version on disk is newer than we can understand then ignore it.
+        return NS_OK;
+      }
+
+      while (hasMoreLines) {
+        rv = i->ReadLine(line, &hasMoreLines);
+        if (NS_WARN_IF(NS_FAILED(rv))) {
+          return rv;
+        }
+        // Read key secondsstamp origin.
+        // Ignore any lines that don't fit format in the comment above exactly.
+        int32_t f = line.FindChar(' ');
+        if (f < 0) {
+          continue;
+        }
+        const nsACString& key = Substring(line, 0, f);
+        const nsACString& s = Substring(line, f+1);
+        f = s.FindChar(' ');
+        if (f < 0) {
+          continue;
+        }
+        int64_t secondsstamp = nsCString(Substring(s, 0, f)).ToInteger64(&rv);
+        if (NS_FAILED(rv)) {
+          continue;
+        }
+        const nsACString& origin = Substring(s, f+1);
+
+        // Validate key
+        if (key.Length() != OriginKey::EncodedLength) {
+          continue;
+        }
+        nsCString dummy;
+        rv = Base64Decode(key, dummy);
+        if (NS_FAILED(rv)) {
+          continue;
+        }
+        mKeys.Put(origin, new OriginKey(key, secondsstamp));
+      }
+      mPersistCount = mKeys.Count();
+      return NS_OK;
+    }
+
+    nsresult
+    Write()
+    {
+      nsCOMPtr<nsIFile> file = GetFile();
+      if (NS_WARN_IF(!file)) {
+        return NS_ERROR_UNEXPECTED;
+      }
+
+      nsCOMPtr<nsIOutputStream> stream;
+      nsresult rv = NS_NewSafeLocalFileOutputStream(getter_AddRefs(stream), file);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+
+      nsAutoCString versionBuffer;
+      versionBuffer.AppendLiteral(ORIGINKEYS_VERSION);
+      versionBuffer.Append('\n');
+
+      uint32_t count;
+      rv = stream->Write(versionBuffer.Data(), versionBuffer.Length(), &count);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      if (count != versionBuffer.Length()) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      for (auto iter = mKeys.Iter(); !iter.Done(); iter.Next()) {
+        const nsACString& origin = iter.Key();
+        OriginKey* originKey = iter.UserData();
+
+        if (!originKey->mSecondsStamp) {
+          continue; // don't write temporal ones
+        }
+
+        nsCString originBuffer;
+        originBuffer.Append(originKey->mKey);
+        originBuffer.Append(' ');
+        originBuffer.AppendInt(originKey->mSecondsStamp);
+        originBuffer.Append(' ');
+        originBuffer.Append(origin);
+        originBuffer.Append('\n');
+
+        rv = stream->Write(originBuffer.Data(), originBuffer.Length(), &count);
+        if (NS_WARN_IF(NS_FAILED(rv)) || count != originBuffer.Length()) {
+          break;
+        }
+      }
+
+      nsCOMPtr<nsISafeOutputStream> safeStream = do_QueryInterface(stream);
+      MOZ_ASSERT(safeStream);
+
+      rv = safeStream->Finish();
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      return NS_OK;
+    }
+
+    nsresult Load()
+    {
+      nsresult rv = Read();
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        Delete();
+      }
+      return rv;
+    }
+
+    nsresult Save()
+    {
+      nsresult rv = Write();
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        NS_WARNING("Failed to write data for EnumerateDevices id-persistence.");
+        Delete();
+      }
+      return rv;
+    }
+
+    void Clear(int64_t aSinceWhen)
+    {
+      OriginKeysTable::Clear(aSinceWhen);
+      Delete();
+      Save();
+    }
+
+    nsresult Delete()
+    {
+      nsCOMPtr<nsIFile> file = GetFile();
+      if (NS_WARN_IF(!file)) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      nsresult rv = file->Remove(false);
+      if (rv == NS_ERROR_FILE_NOT_FOUND) {
+        return NS_OK;
+      }
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
+      return NS_OK;
+    }
+
+    void
+    SetProfileDir(nsIFile* aProfileDir)
+    {
+      MOZ_ASSERT(!NS_IsMainThread());
+      bool first = !mProfileDir;
+      mProfileDir = aProfileDir;
+      // Load from disk when we first get a profileDir, but not subsequently.
+      if (first) {
+        Load();
+      }
+    }
+  private:
+    nsCOMPtr<nsIFile> mProfileDir;
+  };
+
+private:
+  virtual ~OriginKeyStore()
+  {
+    sOriginKeyStore = nullptr;
+    LOG((__FUNCTION__));
+  }
+
+public:
+  static OriginKeyStore* Get()
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+    if (!sOriginKeyStore) {
+      sOriginKeyStore = new OriginKeyStore();
+    }
+    return sOriginKeyStore;
+  }
+
+  // Only accessed on StreamTS thread
+  OriginKeysLoader mOriginKeys;
+  OriginKeysTable mPrivateBrowsingOriginKeys;
+};
+
+NS_IMPL_ISUPPORTS0(OriginKeyStore)
+
+bool NonE10s::SendGetOriginKeyResponse(const uint32_t& aRequestId,
+                                       nsCString aKey) {
+  MediaManager* mgr = MediaManager::GetIfExists();
+  if (!mgr) {
+    return false;
+  }
+  RefPtr<Pledge<nsCString>> pledge = mgr->mGetOriginKeyPledges.Remove(aRequestId);
+  if (pledge) {
+    pledge->Resolve(aKey);
+  }
+  return true;
+}
+
+template<class Super> bool
+Parent<Super>::RecvGetOriginKey(const uint32_t& aRequestId,
+                                const nsCString& aOrigin,
+                                const bool& aPrivateBrowsing,
+                                const bool& aPersist)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // First, get profile dir.
+
+  MOZ_ASSERT(NS_IsMainThread());
+  nsCOMPtr<nsIFile> profileDir;
+  nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                       getter_AddRefs(profileDir));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  // Then over to stream-transport thread to do the actual file io.
+  // Stash a pledge to hold the answer and get an id for this request.
+
+  RefPtr<Pledge<nsCString>> p = new Pledge<nsCString>();
+  uint32_t id = mOutstandingPledges.Append(*p);
+
+  nsCOMPtr<nsIEventTarget> sts = do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
+  MOZ_ASSERT(sts);
+  RefPtr<Parent<Super>> that(this);
+
+  rv = sts->Dispatch(NewRunnableFrom([this, that, id, profileDir, aOrigin,
+                                      aPrivateBrowsing, aPersist]() -> nsresult {
+    MOZ_ASSERT(!NS_IsMainThread());
+    mOriginKeyStore->mOriginKeys.SetProfileDir(profileDir);
+    nsCString result;
+    if (aPrivateBrowsing) {
+      mOriginKeyStore->mPrivateBrowsingOriginKeys.GetOriginKey(aOrigin, result);
+    } else {
+      mOriginKeyStore->mOriginKeys.GetOriginKey(aOrigin, result, aPersist);
+    }
+
+    // Pass result back to main thread.
+    nsresult rv;
+    rv = NS_DispatchToMainThread(NewRunnableFrom([this, that, id,
+                                                  result]() -> nsresult {
+      if (mDestroyed) {
+        return NS_OK;
+      }
+      RefPtr<Pledge<nsCString>> p = mOutstandingPledges.Remove(id);
+      if (!p) {
+        return NS_ERROR_UNEXPECTED;
+      }
+      p->Resolve(result);
+      return NS_OK;
+    }), NS_DISPATCH_NORMAL);
+
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+    return NS_OK;
+  }), NS_DISPATCH_NORMAL);
+
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+  p->Then([this, that, aRequestId](const nsCString& aKey) mutable {
+    if (mDestroyed) {
+      return NS_OK;
+    }
+    Unused << this->SendGetOriginKeyResponse(aRequestId, aKey);
+    return NS_OK;
+  });
+  return true;
+}
+
+template<class Super> bool
+Parent<Super>::RecvSanitizeOriginKeys(const uint64_t& aSinceWhen,
+                                      const bool& aOnlyPrivateBrowsing)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  nsCOMPtr<nsIFile> profileDir;
+  nsresult rv = NS_GetSpecialDirectory(NS_APP_USER_PROFILE_50_DIR,
+                                         getter_AddRefs(profileDir));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+  // Over to stream-transport thread to do the file io.
+
+  nsCOMPtr<nsIEventTarget> sts = do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID);
+  MOZ_ASSERT(sts);
+  RefPtr<OriginKeyStore> store(mOriginKeyStore);
+
+  rv = sts->Dispatch(NewRunnableFrom([profileDir, store, aSinceWhen,
+                                      aOnlyPrivateBrowsing]() -> nsresult {
+    MOZ_ASSERT(!NS_IsMainThread());
+    store->mPrivateBrowsingOriginKeys.Clear(aSinceWhen);
+    if (!aOnlyPrivateBrowsing) {
+      store->mOriginKeys.SetProfileDir(profileDir);
+      store->mOriginKeys.Clear(aSinceWhen);
+    }
+    return NS_OK;
+  }), NS_DISPATCH_NORMAL);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+  return true;
+}
+
+template<class Super> void
+Parent<Super>::ActorDestroy(ActorDestroyReason aWhy)
+{
+  // No more IPC from here
+  mDestroyed = true;
+  LOG((__FUNCTION__));
+}
+
+template<class Super>
+Parent<Super>::Parent()
+  : mOriginKeyStore(OriginKeyStore::Get())
+  , mDestroyed(false)
+{
+  LOG(("media::Parent: %p", this));
+}
+
+template<class Super>
+Parent<Super>::~Parent()
+{
+  LOG(("~media::Parent: %p", this));
+}
+
+PMediaParent*
+AllocPMediaParent()
+{
+  Parent<PMediaParent>* obj = new Parent<PMediaParent>();
+  obj->AddRef();
+  return obj;
+}
+
+bool
+DeallocPMediaParent(media::PMediaParent *aActor)
+{
+  static_cast<Parent<PMediaParent>*>(aActor)->Release();
+  return true;
+}
+
+} // namespace media
+} // namespace mozilla
+
+// Instantiate templates to satisfy linker
+template class mozilla::media::Parent<mozilla::media::NonE10s>;
diff --git a/dom/media/systemservices/MediaParent.h b/dom/media/systemservices/MediaParent.h
new file mode 100644
index 0000000000..b5dcd84ad2
--- /dev/null
+++ b/dom/media/systemservices/MediaParent.h
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MediaParent_h
+#define mozilla_MediaParent_h
+
+#include "MediaChild.h"
+
+#include "mozilla/dom/ContentParent.h"
+#include "mozilla/media/PMediaParent.h"
+
+namespace mozilla {
+namespace media {
+
+// media::Parent implements the chrome-process side of ipc for media::Child APIs
+// A same-process version may also be created to service non-e10s calls.
+
+class OriginKeyStore;
+
+class NonE10s
+{
+  typedef mozilla::ipc::IProtocol::ActorDestroyReason
+      ActorDestroyReason;
+public:
+  virtual ~NonE10s() {}
+protected:
+  virtual bool RecvGetOriginKey(const uint32_t& aRequestId,
+                                const nsCString& aOrigin,
+                                const bool& aPrivateBrowsing,
+                                const bool& aPersist) = 0;
+  virtual bool RecvSanitizeOriginKeys(const uint64_t& aSinceWhen,
+                                      const bool& aOnlyPrivateBrowsing) = 0;
+  virtual void
+  ActorDestroy(ActorDestroyReason aWhy) = 0;
+
+  bool SendGetOriginKeyResponse(const uint32_t& aRequestId,
+                                nsCString aKey);
+};
+
+// Super = PMediaParent or NonE10s
+
+template<class Super>
+class Parent : public Super
+{
+  typedef mozilla::ipc::IProtocol::ActorDestroyReason
+      ActorDestroyReason;
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(Parent<Super>)
+
+  virtual bool RecvGetOriginKey(const uint32_t& aRequestId,
+                                const nsCString& aOrigin,
+                                const bool& aPrivateBrowsing,
+                                const bool& aPersist) override;
+  virtual bool RecvSanitizeOriginKeys(const uint64_t& aSinceWhen,
+                                      const bool& aOnlyPrivateBrowsing) override;
+  virtual void ActorDestroy(ActorDestroyReason aWhy) override;
+
+  Parent();
+private:
+  virtual ~Parent();
+
+  RefPtr<OriginKeyStore> mOriginKeyStore;
+  bool mDestroyed;
+
+  CoatCheck<Pledge<nsCString>> mOutstandingPledges;
+};
+
+PMediaParent* AllocPMediaParent();
+bool DeallocPMediaParent(PMediaParent *aActor);
+
+} // namespace media
+} // namespace mozilla
+
+#endif  // mozilla_MediaParent_h
diff --git a/dom/media/systemservices/MediaSystemResourceClient.cpp b/dom/media/systemservices/MediaSystemResourceClient.cpp
new file mode 100644
index 0000000000..e1ad38aefe
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceClient.cpp
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Monitor.h"
+#include "mozilla/ReentrantMonitor.h"
+
+#include "MediaSystemResourceClient.h"
+
+namespace mozilla {
+
+Atomic<uint32_t> MediaSystemResourceClient::sSerialCounter(0);
+
+MediaSystemResourceClient::MediaSystemResourceClient(MediaSystemResourceType aReourceType)
+  : mResourceType(aReourceType)
+  , mId(++sSerialCounter)
+  , mListener(nullptr)
+  , mResourceState(RESOURCE_STATE_START)
+  , mIsSync(false)
+  , mAcquireSyncWaitMonitor(nullptr)
+  , mAcquireSyncWaitDone(nullptr)
+{
+  mManager = MediaSystemResourceManager::Get();
+  if (mManager) {
+    mManager->Register(this);
+  }
+}
+
+MediaSystemResourceClient::~MediaSystemResourceClient()
+{
+  ReleaseResource();
+  if (mManager) {
+    mManager->Unregister(this);
+  }
+}
+
+bool
+MediaSystemResourceClient::SetListener(MediaSystemResourceReservationListener* aListener)
+{
+  if (!mManager) {
+    return false;
+  }
+  return mManager->SetListener(this, aListener);
+}
+
+void
+MediaSystemResourceClient::Acquire()
+{
+  if (!mManager) {
+    return;
+  }
+  mManager->Acquire(this);
+}
+
+bool
+MediaSystemResourceClient::AcquireSyncNoWait()
+{
+  if (!mManager) {
+    return false;
+  }
+  return mManager->AcquireSyncNoWait(this);
+}
+
+void
+MediaSystemResourceClient::ReleaseResource()
+{
+  if (!mManager) {
+    return;
+  }
+  mManager->ReleaseResource(this);
+}
+
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaSystemResourceClient.h b/dom/media/systemservices/MediaSystemResourceClient.h
new file mode 100644
index 0000000000..29e769a92d
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceClient.h
@@ -0,0 +1,94 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceClient_h_)
+#define MediaSystemResourceClient_h_
+
+#include "MediaSystemResourceManager.h"
+#include "MediaSystemResourceTypes.h"
+#include "mozilla/Atomics.h"
+#include "mozilla/media/MediaSystemResourceTypes.h"
+#include "mozilla/Monitor.h"
+#include "mozilla/RefPtr.h"
+
+namespace mozilla {
+
+class MediaSystemResourceManager;
+
+
+/**
+ * This is a base class for listener callbacks.
+ * This callback is invoked when the media system resource reservation state
+ * is changed.
+ */
+class MediaSystemResourceReservationListener {
+public:
+  virtual void ResourceReserved() = 0;
+  virtual void ResourceReserveFailed() = 0;
+};
+
+/**
+ * MediaSystemResourceClient is used to reserve a media system resource
+ * like hw decoder. When system has a limitation of a media resource,
+ * use this class to mediate use rights of the resource.
+ */
+class MediaSystemResourceClient
+{
+public:
+
+  // Enumeration for the valid decoding states
+  enum ResourceState {
+    RESOURCE_STATE_START,
+    RESOURCE_STATE_WAITING,
+    RESOURCE_STATE_ACQUIRED,
+    RESOURCE_STATE_NOT_ACQUIRED,
+    RESOURCE_STATE_END
+  };
+
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaSystemResourceClient)
+
+  explicit MediaSystemResourceClient(MediaSystemResourceType aReourceType);
+
+  bool SetListener(MediaSystemResourceReservationListener* aListener);
+
+  // Try to acquire media resource asynchronously.
+  // If the resource is used by others, wait until acquired.
+  void Acquire();
+
+  // Try to acquire media resource synchronously. If the resource is not immediately
+  // available, fail to acquire it.
+  // return false if resource is not acquired.
+  // return true if resource is acquired.
+  //
+  // This function should not be called on ImageBridge thread.
+  // It should be used only for compatibility with legacy code.
+  bool AcquireSyncNoWait();
+
+  void ReleaseResource();
+
+private:
+  ~MediaSystemResourceClient();
+
+  RefPtr<MediaSystemResourceManager> mManager;
+  const MediaSystemResourceType mResourceType;
+  const uint32_t mId;
+
+  // Modified only by MediaSystemResourceManager.
+  // Accessed and modified with MediaSystemResourceManager::mReentrantMonitor held.
+  MediaSystemResourceReservationListener* mListener;
+  ResourceState mResourceState;
+  bool mIsSync;
+  ReentrantMonitor* mAcquireSyncWaitMonitor;
+  bool* mAcquireSyncWaitDone;
+
+  static mozilla::Atomic<uint32_t> sSerialCounter;
+
+  friend class MediaSystemResourceManager;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceManager.cpp b/dom/media/systemservices/MediaSystemResourceManager.cpp
new file mode 100644
index 0000000000..29db0ef3ea
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManager.cpp
@@ -0,0 +1,387 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/TaskQueue.h"
+
+#include "gfxPrefs.h"
+#include "MediaSystemResourceManagerChild.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+
+#include "MediaSystemResourceManager.h"
+
+namespace mozilla {
+
+using namespace mozilla::ipc;
+using namespace mozilla::layers;
+
+/* static */ StaticRefPtr<MediaSystemResourceManager> MediaSystemResourceManager::sSingleton;
+
+/* static */ MediaSystemResourceManager*
+MediaSystemResourceManager::Get()
+{
+  if (sSingleton) {
+    return sSingleton;
+  }
+  MediaSystemResourceManager::Init();
+  return sSingleton;
+}
+
+/* static */ void
+MediaSystemResourceManager::Shutdown()
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+  if (sSingleton) {
+    sSingleton->CloseIPC();
+    sSingleton = nullptr;
+  }
+}
+
+/* static */ void
+MediaSystemResourceManager::Init()
+{
+  RefPtr<ImageBridgeChild> imageBridge = ImageBridgeChild::GetSingleton();
+  if (!imageBridge) {
+    NS_WARNING("ImageBridge does not exist");
+    return;
+  }
+
+  if (InImageBridgeChildThread()) {
+    if (!sSingleton) {
+#ifdef DEBUG
+      static int timesCreated = 0;
+      timesCreated++;
+      MOZ_ASSERT(timesCreated == 1);
+#endif
+      sSingleton = new MediaSystemResourceManager();
+    }
+    return;
+  }
+
+  ReentrantMonitor barrier("MediaSystemResourceManager::Init");
+  ReentrantMonitorAutoEnter mainThreadAutoMon(barrier);
+  bool done = false;
+
+  RefPtr<Runnable> runnable =
+    NS_NewRunnableFunction([&]() {
+      if (!sSingleton) {
+        sSingleton = new MediaSystemResourceManager();
+      }
+      ReentrantMonitorAutoEnter childThreadAutoMon(barrier);
+      done = true;
+      barrier.NotifyAll();
+    });
+
+  imageBridge->GetMessageLoop()->PostTask(runnable.forget());
+
+  // should stop the thread until done.
+  while (!done) {
+    barrier.Wait();
+  }
+}
+
+MediaSystemResourceManager::MediaSystemResourceManager()
+  : mReentrantMonitor("MediaSystemResourceManager.mReentrantMonitor")
+  , mShutDown(false)
+  , mChild(nullptr)
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+  OpenIPC();
+}
+
+MediaSystemResourceManager::~MediaSystemResourceManager()
+{
+  MOZ_ASSERT(IsIpcClosed());
+}
+
+void
+MediaSystemResourceManager::OpenIPC()
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+  MOZ_ASSERT(!mChild);
+
+  media::PMediaSystemResourceManagerChild* child =
+    ImageBridgeChild::GetSingleton()->SendPMediaSystemResourceManagerConstructor();
+  mChild = static_cast<media::MediaSystemResourceManagerChild*>(child);
+  mChild->SetManager(this);
+}
+
+void
+MediaSystemResourceManager::CloseIPC()
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+
+  if (!mChild) {
+    return;
+  }
+  mChild->Destroy();
+  mChild = nullptr;
+  mShutDown = true;
+}
+
+void
+MediaSystemResourceManager::OnIpcClosed()
+{
+  mChild = nullptr;
+}
+
+bool
+MediaSystemResourceManager::IsIpcClosed()
+{
+  return mChild ? true : false;
+}
+
+void
+MediaSystemResourceManager::Register(MediaSystemResourceClient* aClient)
+{
+  ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+  MOZ_ASSERT(aClient);
+  MOZ_ASSERT(!mResourceClients.Get(aClient->mId));
+
+  mResourceClients.Put(aClient->mId, aClient);
+}
+
+void
+MediaSystemResourceManager::Unregister(MediaSystemResourceClient* aClient)
+{
+  ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+  MOZ_ASSERT(aClient);
+  MOZ_ASSERT(mResourceClients.Get(aClient->mId));
+  MOZ_ASSERT(mResourceClients.Get(aClient->mId) == aClient);
+
+  mResourceClients.Remove(aClient->mId);
+}
+
+bool
+MediaSystemResourceManager::SetListener(MediaSystemResourceClient* aClient,
+                                  MediaSystemResourceReservationListener* aListener)
+{
+  ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+  MOZ_ASSERT(aClient);
+
+  MediaSystemResourceClient* client = mResourceClients.Get(aClient->mId);
+  MOZ_ASSERT(client);
+
+  if (!client) {
+    return false;
+  }
+  // State Check
+  if (aClient->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_START) {
+    return false;
+  }
+  aClient->mListener = aListener;
+  return true;
+}
+
+void
+MediaSystemResourceManager::Acquire(MediaSystemResourceClient* aClient)
+{
+  MOZ_ASSERT(aClient);
+  MOZ_ASSERT(!InImageBridgeChildThread());
+
+  ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+  MediaSystemResourceClient* client = mResourceClients.Get(aClient->mId);
+  MOZ_ASSERT(client);
+  MOZ_ASSERT(client == aClient);
+
+  aClient->mIsSync = false; // async request
+
+  if (!client) {
+    HandleAcquireResult(aClient->mId, false);
+    return;
+  }
+  // State Check
+  if (aClient->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_START) {
+    HandleAcquireResult(aClient->mId, false);
+    return;
+  }
+  aClient->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_WAITING;
+  ImageBridgeChild::GetSingleton()->GetMessageLoop()->PostTask(
+    NewRunnableMethod<uint32_t>(
+      this,
+      &MediaSystemResourceManager::DoAcquire,
+      aClient->mId));
+}
+
+bool
+MediaSystemResourceManager::AcquireSyncNoWait(MediaSystemResourceClient* aClient)
+{
+  MOZ_ASSERT(aClient);
+  MOZ_ASSERT(!InImageBridgeChildThread());
+
+  ReentrantMonitor barrier("MediaSystemResourceManager::AcquireSyncNoWait");
+  ReentrantMonitorAutoEnter autoMon(barrier);
+  bool done = false;
+  {
+    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+    MediaSystemResourceClient* client = mResourceClients.Get(aClient->mId);
+    MOZ_ASSERT(client);
+    MOZ_ASSERT(client == aClient);
+
+    aClient->mIsSync = true; // sync request
+
+    if (InImageBridgeChildThread()) {
+      HandleAcquireResult(aClient->mId, false);
+      return false;
+    }
+    if (!client || client != aClient) {
+      HandleAcquireResult(aClient->mId, false);
+      return false;
+    }
+    // State Check
+    if (aClient->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_START) {
+      HandleAcquireResult(aClient->mId, false);
+      return false;
+    }
+    // Hold barrier Monitor until acquire task end.
+    aClient->mAcquireSyncWaitMonitor = &barrier;
+    aClient->mAcquireSyncWaitDone = &done;
+    aClient->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_WAITING;
+  }
+
+  ImageBridgeChild::GetSingleton()->GetMessageLoop()->PostTask(
+    NewRunnableMethod<uint32_t>(
+      this,
+      &MediaSystemResourceManager::DoAcquire,
+      aClient->mId));
+
+  // should stop the thread until done.
+  while (!done) {
+    barrier.Wait();
+  }
+
+  {
+    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+    if (aClient->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_ACQUIRED) {
+      return false;
+    }
+    return true;
+  }
+}
+
+void
+MediaSystemResourceManager::DoAcquire(uint32_t aId)
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+  if (mShutDown || !mChild) {
+    HandleAcquireResult(aId, false);
+    return;
+  }
+  {
+    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+    MediaSystemResourceClient* client = mResourceClients.Get(aId);
+    MOZ_ASSERT(client);
+
+    if (!client ||
+        client->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_WAITING) {
+      HandleAcquireResult(aId, false);
+      return;
+    }
+    MOZ_ASSERT(aId == client->mId);
+    bool willWait = !client->mAcquireSyncWaitMonitor ? true : false;
+    mChild->SendAcquire(client->mId,
+                        client->mResourceType,
+                        willWait);
+  }
+}
+
+void
+MediaSystemResourceManager::ReleaseResource(MediaSystemResourceClient* aClient)
+{
+  MOZ_ASSERT(aClient);
+  {
+    ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+    MediaSystemResourceClient* client = mResourceClients.Get(aClient->mId);
+    MOZ_ASSERT(client);
+    MOZ_ASSERT(client == aClient);
+
+    if (!client ||
+        client != aClient ||
+        aClient->mResourceState == MediaSystemResourceClient::RESOURCE_STATE_START ||
+        aClient->mResourceState == MediaSystemResourceClient::RESOURCE_STATE_END) {
+
+      aClient->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_END;
+      return;
+    }
+
+    aClient->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_END;
+
+    ImageBridgeChild::GetSingleton()->GetMessageLoop()->PostTask(
+      NewRunnableMethod<uint32_t>(
+        this,
+        &MediaSystemResourceManager::DoRelease,
+        aClient->mId));
+  }
+}
+
+void
+MediaSystemResourceManager::DoRelease(uint32_t aId)
+{
+  MOZ_ASSERT(InImageBridgeChildThread());
+  if (mShutDown || !mChild) {
+    return;
+  }
+  mChild->SendRelease(aId);
+}
+
+void
+MediaSystemResourceManager::RecvResponse(uint32_t aId, bool aSuccess)
+{
+  HandleAcquireResult(aId, aSuccess);
+}
+
+void
+MediaSystemResourceManager::HandleAcquireResult(uint32_t aId, bool aSuccess)
+{
+  if (!InImageBridgeChildThread()) {
+    ImageBridgeChild::GetSingleton()->GetMessageLoop()->PostTask(
+      NewRunnableMethod<uint32_t, bool>(
+        this,
+        &MediaSystemResourceManager::HandleAcquireResult,
+        aId,
+        aSuccess));
+    return;
+  }
+
+  ReentrantMonitorAutoEnter mon(mReentrantMonitor);
+  MediaSystemResourceClient* client = mResourceClients.Get(aId);
+  if (!client) {
+    // Client was already unregistered.
+    return;
+  }
+  if (client->mResourceState != MediaSystemResourceClient::RESOURCE_STATE_WAITING) {
+    return;
+  }
+
+  // Update state
+  if (aSuccess) {
+    client->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_ACQUIRED;
+  } else {
+    client->mResourceState = MediaSystemResourceClient::RESOURCE_STATE_NOT_ACQUIRED;
+  }
+
+  if (client->mIsSync) {
+    if (client->mAcquireSyncWaitMonitor) {
+      // Notify AcquireSync() complete
+      MOZ_ASSERT(client->mAcquireSyncWaitDone);
+      ReentrantMonitorAutoEnter autoMon(*client->mAcquireSyncWaitMonitor);
+      *client->mAcquireSyncWaitDone = true;
+      client->mAcquireSyncWaitMonitor->NotifyAll();
+      client->mAcquireSyncWaitMonitor = nullptr;
+      client->mAcquireSyncWaitDone = nullptr;
+    }
+  } else {
+    // Notify Acquire() result
+    if (client->mListener) {
+      if (aSuccess) {
+        client->mListener->ResourceReserved();
+      } else {
+       client->mListener->ResourceReserveFailed();
+      }
+    }
+  }
+}
+
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaSystemResourceManager.h b/dom/media/systemservices/MediaSystemResourceManager.h
new file mode 100644
index 0000000000..36869e2026
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManager.h
@@ -0,0 +1,82 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceManager_h_)
+#define MediaSystemResourceManager_h_
+
+#include <queue>
+
+#include "MediaSystemResourceTypes.h"
+#include "mozilla/ReentrantMonitor.h"
+#include "mozilla/StaticPtr.h"
+#include "nsDataHashtable.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+
+namespace media {
+class MediaSystemResourceManagerChild;
+} // namespace media
+
+class MediaSystemResourceClient;
+class MediaSystemResourceReservationListener;
+class ReentrantMonitor;
+class TaskQueue;
+
+/**
+ * Manage media system resource allocation requests within a process.
+ */
+class MediaSystemResourceManager
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaSystemResourceManager)
+
+  static MediaSystemResourceManager* Get();
+  static void Init();
+  static void Shutdown();
+
+  void OnIpcClosed();
+
+  void Register(MediaSystemResourceClient* aClient);
+  void Unregister(MediaSystemResourceClient* aClient);
+
+  bool SetListener(MediaSystemResourceClient* aClient,
+                   MediaSystemResourceReservationListener* aListener);
+
+  void Acquire(MediaSystemResourceClient* aClient);
+  bool AcquireSyncNoWait(MediaSystemResourceClient* aClient);
+  void ReleaseResource(MediaSystemResourceClient* aClient);
+
+  void RecvResponse(uint32_t aId, bool aSuccess);
+
+private:
+  MediaSystemResourceManager();
+  virtual ~MediaSystemResourceManager();
+
+  void OpenIPC();
+  void CloseIPC();
+  bool IsIpcClosed();
+
+  void DoAcquire(uint32_t aId);
+
+  void DoRelease(uint32_t aId);
+
+  void HandleAcquireResult(uint32_t aId, bool aSuccess);
+
+  ReentrantMonitor mReentrantMonitor;
+
+  bool mShutDown;
+
+  media::MediaSystemResourceManagerChild* mChild;
+
+  nsDataHashtable<nsUint32HashKey, MediaSystemResourceClient*> mResourceClients;
+
+  static StaticRefPtr<MediaSystemResourceManager> sSingleton;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceManagerChild.cpp b/dom/media/systemservices/MediaSystemResourceManagerChild.cpp
new file mode 100644
index 0000000000..2844738217
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManagerChild.cpp
@@ -0,0 +1,53 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaSystemResourceManager.h"
+
+#include "MediaSystemResourceManagerChild.h"
+
+namespace mozilla {
+namespace media {
+
+MediaSystemResourceManagerChild::MediaSystemResourceManagerChild()
+  : mDestroyed(false)
+{
+}
+
+MediaSystemResourceManagerChild::~MediaSystemResourceManagerChild()
+{
+}
+
+bool
+MediaSystemResourceManagerChild::RecvResponse(const uint32_t& aId,
+                                              const bool& aSuccess)
+{
+  if (mManager) {
+    mManager->RecvResponse(aId, aSuccess);
+  }
+  return true;
+}
+
+void
+MediaSystemResourceManagerChild::ActorDestroy(ActorDestroyReason aActorDestroyReason)
+{
+  MOZ_ASSERT(!mDestroyed);
+  if (mManager) {
+    mManager->OnIpcClosed();
+  }
+  mDestroyed = true;
+}
+
+void
+MediaSystemResourceManagerChild::Destroy()
+{
+  if (mDestroyed) {
+    return;
+  }
+  SendRemoveResourceManager();
+  // WARNING: |this| is dead, hands off
+}
+
+} // namespace media
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaSystemResourceManagerChild.h b/dom/media/systemservices/MediaSystemResourceManagerChild.h
new file mode 100644
index 0000000000..51d4de8d13
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManagerChild.h
@@ -0,0 +1,66 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceManagerChild_h_)
+#define MediaSystemResourceManagerChild_h_
+
+#include "mozilla/media/PMediaSystemResourceManagerChild.h"
+#include "nsISupportsImpl.h"
+
+namespace mozilla {
+
+class MediaSystemResourceManager;
+
+namespace ipc {
+class BackgroundChildImpl;
+} // namespace ipc
+
+namespace media {
+
+/**
+ * Handle MediaSystemResourceManager's IPC
+ */
+class MediaSystemResourceManagerChild final : public PMediaSystemResourceManagerChild
+{
+public:
+  struct ResourceListener {
+    /* The resource is reserved and can be granted.
+     * The client can allocate the requested resource.
+     */
+    virtual void resourceReserved() = 0;
+    /* The resource is not reserved any more.
+     * The client should release the resource as soon as possible if the
+     * resource is still being held.
+     */
+    virtual void resourceCanceled() = 0;
+  };
+
+  MediaSystemResourceManagerChild();
+  virtual ~MediaSystemResourceManagerChild();
+
+  void Destroy();
+
+  void SetManager(MediaSystemResourceManager* aManager)
+  {
+    mManager = aManager;
+  }
+
+protected:
+  bool RecvResponse(const uint32_t& aId,
+                    const bool& aSuccess) override;
+
+private:
+  void ActorDestroy(ActorDestroyReason aActorDestroyReason) override;
+
+  bool mDestroyed;
+  MediaSystemResourceManager* mManager;
+
+  friend class mozilla::ipc::BackgroundChildImpl;
+};
+
+} // namespace media
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceManagerParent.cpp b/dom/media/systemservices/MediaSystemResourceManagerParent.cpp
new file mode 100644
index 0000000000..9e15c0c48a
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManagerParent.cpp
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Unused.h"
+
+#include "MediaSystemResourceManagerParent.h"
+
+namespace mozilla {
+namespace media {
+
+using namespace ipc;
+
+MediaSystemResourceManagerParent::MediaSystemResourceManagerParent()
+  : mDestroyed(false)
+{
+  mMediaSystemResourceService = MediaSystemResourceService::Get();
+}
+
+MediaSystemResourceManagerParent::~MediaSystemResourceManagerParent()
+{
+  MOZ_ASSERT(mDestroyed);
+}
+
+bool
+MediaSystemResourceManagerParent::RecvAcquire(const uint32_t& aId,
+                                              const MediaSystemResourceType& aResourceType,
+                                              const bool& aWillWait)
+{
+  MediaSystemResourceRequest* request = mResourceRequests.Get(aId);
+  MOZ_ASSERT(!request);
+  if (request) {
+    // Send fail response
+    mozilla::Unused << SendResponse(aId, false /* fail */);
+    return true;
+  }
+
+  request = new MediaSystemResourceRequest(aId, aResourceType);
+  mResourceRequests.Put(aId, request);
+  mMediaSystemResourceService->Acquire(this, aId, aResourceType, aWillWait);
+  return true;
+}
+
+bool
+MediaSystemResourceManagerParent::RecvRelease(const uint32_t& aId)
+{
+  MediaSystemResourceRequest* request = mResourceRequests.Get(aId);
+  if (!request) {
+    return true;
+  }
+
+  mMediaSystemResourceService->ReleaseResource(this, aId, request->mResourceType);
+  mResourceRequests.Remove(aId);
+  return true;
+}
+
+bool
+MediaSystemResourceManagerParent::RecvRemoveResourceManager()
+{
+  return PMediaSystemResourceManagerParent::Send__delete__(this);
+}
+
+void
+MediaSystemResourceManagerParent::ActorDestroy(ActorDestroyReason aReason)
+{
+  MOZ_ASSERT(!mDestroyed);
+
+  // Release all resource requests of the MediaSystemResourceManagerParent.
+  // Clears all remaining pointers to this object. 
+  mMediaSystemResourceService->ReleaseResource(this);
+
+  mDestroyed = true;
+}
+
+} // namespace media
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaSystemResourceManagerParent.h b/dom/media/systemservices/MediaSystemResourceManagerParent.h
new file mode 100644
index 0000000000..9080cb3855
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceManagerParent.h
@@ -0,0 +1,57 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceManagerParent_h_)
+#define MediaSystemResourceManagerParent_h_
+
+#include "MediaSystemResourceManager.h"
+#include "MediaSystemResourceService.h"
+#include "MediaSystemResourceTypes.h"
+#include "mozilla/media/PMediaSystemResourceManagerParent.h"
+
+namespace mozilla {
+namespace media {
+
+/**
+ * Handle MediaSystemResourceManager's IPC
+ */
+class MediaSystemResourceManagerParent final : public PMediaSystemResourceManagerParent
+{
+public:
+  MediaSystemResourceManagerParent();
+  virtual ~MediaSystemResourceManagerParent();
+
+protected:
+  bool RecvAcquire(const uint32_t& aId,
+                   const MediaSystemResourceType& aResourceType,
+                   const bool& aWillWait) override;
+
+  bool RecvRelease(const uint32_t& aId) override;
+
+  bool RecvRemoveResourceManager() override;
+
+private:
+  void ActorDestroy(ActorDestroyReason aActorDestroyReason) override;
+
+  struct MediaSystemResourceRequest {
+    MediaSystemResourceRequest()
+      : mId(-1), mResourceType(MediaSystemResourceType::INVALID_RESOURCE) {}
+    MediaSystemResourceRequest(uint32_t aId, MediaSystemResourceType aResourceType)
+      : mId(aId), mResourceType(aResourceType) {}
+    int32_t mId;
+    MediaSystemResourceType mResourceType;
+  };
+
+  bool mDestroyed;
+
+  RefPtr<MediaSystemResourceService> mMediaSystemResourceService;
+
+  nsClassHashtable<nsUint32HashKey, MediaSystemResourceRequest> mResourceRequests;
+};
+
+} // namespace media
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceMessageUtils.h b/dom/media/systemservices/MediaSystemResourceMessageUtils.h
new file mode 100644
index 0000000000..851fbb2532
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceMessageUtils.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceMessageUtils_h_)
+#define MediaSystemResourceMessageUtils_h_
+
+#include "ipc/IPCMessageUtils.h"
+#include "MediaSystemResourceTypes.h"
+
+namespace IPC {
+
+template <>
+struct ParamTraits<mozilla::MediaSystemResourceType>
+  : public ContiguousEnumSerializer<
+             mozilla::MediaSystemResourceType,
+             mozilla::MediaSystemResourceType::VIDEO_DECODER,
+             mozilla::MediaSystemResourceType::INVALID_RESOURCE>
+{};
+
+} // namespace IPC
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceService.cpp b/dom/media/systemservices/MediaSystemResourceService.cpp
new file mode 100644
index 0000000000..0e5d6a50ce
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceService.cpp
@@ -0,0 +1,256 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaSystemResourceManagerParent.h"
+#include "mozilla/layers/CompositorThread.h"
+#include "mozilla/Unused.h"
+
+#include "MediaSystemResourceService.h"
+
+using namespace mozilla::layers;
+
+namespace mozilla {
+
+/* static */ StaticRefPtr<MediaSystemResourceService> MediaSystemResourceService::sSingleton;
+
+/* static */ MediaSystemResourceService*
+MediaSystemResourceService::Get()
+{
+  if (sSingleton) {
+    return sSingleton;
+  }
+  Init();
+  return sSingleton;
+}
+
+/* static */ void
+MediaSystemResourceService::Init()
+{
+  if (!sSingleton) {
+    sSingleton = new MediaSystemResourceService();
+  }
+}
+
+/* static */ void
+MediaSystemResourceService::Shutdown()
+{
+  if (sSingleton) {
+    sSingleton->Destroy();
+    sSingleton = nullptr;
+  }
+}
+
+MediaSystemResourceService::MediaSystemResourceService()
+  : mDestroyed(false)
+{
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
+#ifdef MOZ_WIDGET_GONK
+  // The maximum number of hardware resoureces available.
+  // XXX need to hange to a dynamic way.
+  enum
+  {
+    VIDEO_DECODER_COUNT = 1,
+    VIDEO_ENCODER_COUNT = 1
+  };
+
+  MediaSystemResource* resource;
+
+  resource = new MediaSystemResource(VIDEO_DECODER_COUNT);
+  mResources.Put(static_cast<uint32_t>(MediaSystemResourceType::VIDEO_DECODER), resource);
+
+  resource = new MediaSystemResource(VIDEO_ENCODER_COUNT);
+  mResources.Put(static_cast<uint32_t>(MediaSystemResourceType::VIDEO_ENCODER), resource);
+#endif
+}
+
+MediaSystemResourceService::~MediaSystemResourceService()
+{
+}
+
+void
+MediaSystemResourceService::Destroy()
+{
+  mDestroyed = true;
+}
+
+void
+MediaSystemResourceService::Acquire(media::MediaSystemResourceManagerParent* aParent,
+                                    uint32_t aId,
+                                    MediaSystemResourceType aResourceType,
+                                    bool aWillWait)
+{
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(aParent);
+
+  if (mDestroyed) {
+    return;
+  }
+
+  MediaSystemResource* resource = mResources.Get(static_cast<uint32_t>(aResourceType));
+
+  if (!resource ||
+      resource->mResourceCount == 0) {
+    // Resource does not exit
+    // Send fail response
+    mozilla::Unused << aParent->SendResponse(aId, false /* fail */);
+    return;
+  }
+
+  // Try to acquire a resource
+  if (resource->mAcquiredRequests.size() < resource->mResourceCount) {
+    // Resource is available
+    resource->mAcquiredRequests.push_back(
+      MediaSystemResourceRequest(aParent, aId));
+    // Send success response
+    mozilla::Unused << aParent->SendResponse(aId, true /* success */);
+    return;
+  } else if (!aWillWait) {
+    // Resource is not available and do not wait.
+    // Send fail response
+    mozilla::Unused << aParent->SendResponse(aId, false /* fail */);
+    return;
+  }
+  // Wait until acquire.
+  resource->mWaitingRequests.push_back(
+    MediaSystemResourceRequest(aParent, aId));
+}
+
+void
+MediaSystemResourceService::ReleaseResource(media::MediaSystemResourceManagerParent* aParent,
+                                            uint32_t aId,
+                                            MediaSystemResourceType aResourceType)
+{
+  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
+  MOZ_ASSERT(aParent);
+
+  if (mDestroyed) {
+    return;
+  }
+
+  MediaSystemResource* resource = mResources.Get(static_cast<uint32_t>(aResourceType));
+
+  if (!resource ||
+      resource->mResourceCount == 0) {
+    // Resource does not exit
+    return;
+  }
+  RemoveRequest(aParent, aId, aResourceType);
+  UpdateRequests(aResourceType);
+}
+
+void
+MediaSystemResourceService::ReleaseResource(media::MediaSystemResourceManagerParent* aParent)
+{
+  MOZ_ASSERT(aParent);
+
+  if (mDestroyed) {
+    return;
+  }
+
+  for (auto iter = mResources.Iter(); !iter.Done(); iter.Next()) {
+    const uint32_t& key = iter.Key();
+    RemoveRequests(aParent, static_cast<MediaSystemResourceType>(key));
+    UpdateRequests(static_cast<MediaSystemResourceType>(key));
+  }
+}
+
+void
+MediaSystemResourceService::RemoveRequest(media::MediaSystemResourceManagerParent* aParent,
+                                          uint32_t aId,
+                                          MediaSystemResourceType aResourceType)
+{
+  MOZ_ASSERT(aParent);
+
+  MediaSystemResource* resource = mResources.Get(static_cast<uint32_t>(aResourceType));
+  if (!resource) {
+    return;
+  }
+
+  std::deque<MediaSystemResourceRequest>::iterator it;
+  std::deque<MediaSystemResourceRequest>& acquiredRequests =
+    resource->mAcquiredRequests;
+  for (it = acquiredRequests.begin(); it != acquiredRequests.end(); it++) {
+    if (((*it).mParent == aParent) && ((*it).mId == aId)) {
+      acquiredRequests.erase(it);
+      return;
+    }
+  }
+
+  std::deque<MediaSystemResourceRequest>& waitingRequests =
+    resource->mWaitingRequests;
+  for (it = waitingRequests.begin(); it != waitingRequests.end(); it++) {
+    if (((*it).mParent == aParent) && ((*it).mId == aId)) {
+      waitingRequests.erase(it);
+      return;
+    }
+  }
+}
+
+void
+MediaSystemResourceService::RemoveRequests(media::MediaSystemResourceManagerParent* aParent,
+                                           MediaSystemResourceType aResourceType)
+{
+  MOZ_ASSERT(aParent);
+
+  MediaSystemResource* resource = mResources.Get(static_cast<uint32_t>(aResourceType));
+
+  if (!resource ||
+      resource->mResourceCount == 0) {
+    // Resource does not exit
+    return;
+  }
+
+  std::deque<MediaSystemResourceRequest>::iterator it;
+  std::deque<MediaSystemResourceRequest>& acquiredRequests =
+    resource->mAcquiredRequests;
+  for (it = acquiredRequests.begin(); it != acquiredRequests.end();) {
+    if ((*it).mParent == aParent) {
+      it = acquiredRequests.erase(it);
+    } else {
+      it++;
+    }
+  }
+
+  std::deque<MediaSystemResourceRequest>& waitingRequests =
+    resource->mWaitingRequests;
+  for (it = waitingRequests.begin(); it != waitingRequests.end();) {
+    if ((*it).mParent == aParent) {
+      it = waitingRequests.erase(it);
+    } else {
+      it++;
+    }
+  }
+}
+
+void
+MediaSystemResourceService::UpdateRequests(MediaSystemResourceType aResourceType)
+{
+  MediaSystemResource* resource = mResources.Get(static_cast<uint32_t>(aResourceType));
+
+  if (!resource ||
+      resource->mResourceCount == 0) {
+    // Resource does not exit
+    return;
+  }
+
+  std::deque<MediaSystemResourceRequest>& acquiredRequests =
+    resource->mAcquiredRequests;
+  std::deque<MediaSystemResourceRequest>& waitingRequests =
+    resource->mWaitingRequests;
+
+  while ((acquiredRequests.size() < resource->mResourceCount) &&
+         (waitingRequests.size() > 0)) {
+    MediaSystemResourceRequest& request = waitingRequests.front();
+    MOZ_ASSERT(request.mParent);
+    // Send response
+    mozilla::Unused << request.mParent->SendResponse(request.mId, true /* success */);
+    // Move request to mAcquiredRequests
+    acquiredRequests.push_back(waitingRequests.front());
+    waitingRequests.pop_front();
+  }
+}
+
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaSystemResourceService.h b/dom/media/systemservices/MediaSystemResourceService.h
new file mode 100644
index 0000000000..06e1b537cc
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceService.h
@@ -0,0 +1,89 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceService_h_)
+#define MediaSystemResourceService_h_
+
+#include <deque>
+
+#include "MediaSystemResourceTypes.h"
+#include "mozilla/StaticPtr.h"
+#include "nsClassHashtable.h"
+
+namespace mozilla {
+
+namespace media {
+class MediaSystemResourceManagerParent;
+} // namespace media
+
+/**
+ * Manage media system resource allocation requests within system.
+ */
+class MediaSystemResourceService
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaSystemResourceService)
+
+  static MediaSystemResourceService* Get();
+  static void Init();
+  static void Shutdown();
+
+  void Acquire(media::MediaSystemResourceManagerParent* aParent,
+               uint32_t aId,
+               MediaSystemResourceType aResourceType,
+               bool aWillWait);
+
+  void ReleaseResource(media::MediaSystemResourceManagerParent* aParent,
+                       uint32_t aId,
+                       MediaSystemResourceType aResourceType);
+
+  void ReleaseResource(media::MediaSystemResourceManagerParent* aParent);
+
+private:
+  MediaSystemResourceService();
+  ~MediaSystemResourceService();
+
+  struct MediaSystemResourceRequest {
+    MediaSystemResourceRequest()
+      : mParent(nullptr), mId(-1) {}
+    MediaSystemResourceRequest(media::MediaSystemResourceManagerParent* aParent, uint32_t aId)
+      : mParent(aParent), mId(aId) {}
+    media::MediaSystemResourceManagerParent* mParent;
+    uint32_t mId;
+  };
+
+  struct MediaSystemResource {
+    MediaSystemResource()
+      : mResourceCount(0) {}
+    explicit MediaSystemResource(uint32_t aResourceCount)
+      : mResourceCount(aResourceCount) {}
+
+    std::deque<MediaSystemResourceRequest> mWaitingRequests;
+    std::deque<MediaSystemResourceRequest> mAcquiredRequests;
+    uint32_t mResourceCount;
+  };
+
+  void Destroy();
+
+  void RemoveRequest(media::MediaSystemResourceManagerParent* aParent,
+                     uint32_t aId,
+                     MediaSystemResourceType aResourceType);
+
+  void RemoveRequests(media::MediaSystemResourceManagerParent* aParent,
+                      MediaSystemResourceType aResourceType);
+
+  void UpdateRequests(MediaSystemResourceType aResourceType);
+
+  bool mDestroyed;
+
+  nsClassHashtable<nsUint32HashKey, MediaSystemResource> mResources;
+
+  static StaticRefPtr<MediaSystemResourceService> sSingleton;
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaSystemResourceTypes.h b/dom/media/systemservices/MediaSystemResourceTypes.h
new file mode 100644
index 0000000000..3257d89d29
--- /dev/null
+++ b/dom/media/systemservices/MediaSystemResourceTypes.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#if !defined(MediaSystemResourceTypes_h_)
+#define MediaSystemResourceTypes_h_
+
+namespace mozilla {
+
+enum class MediaSystemResourceType : uint32_t {
+  VIDEO_DECODER = 0,
+  AUDIO_DECODER,  // Not supported currently.
+  VIDEO_ENCODER,
+  AUDIO_ENCODER,  // Not supported currently.
+  CAMERA,          // Not supported currently.
+  INVALID_RESOURCE,
+};
+
+} // namespace mozilla
+
+#endif
diff --git a/dom/media/systemservices/MediaTaskUtils.h b/dom/media/systemservices/MediaTaskUtils.h
new file mode 100644
index 0000000000..c9b64fd2a4
--- /dev/null
+++ b/dom/media/systemservices/MediaTaskUtils.h
@@ -0,0 +1,50 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MediaTaskUtils_h
+#define mozilla_MediaTaskUtils_h
+
+#include "nsThreadUtils.h"
+
+// The main reason this file is separate from MediaUtils.h
+#include "base/task.h"
+
+namespace mozilla {
+namespace media {
+
+/* media::NewTaskFrom() - Create a Task from a lambda.
+ *
+ * Similar to media::NewRunnableFrom() - Create an nsRunnable from a lambda.
+ */
+
+template<typename OnRunType>
+class LambdaTask : public Runnable
+{
+public:
+  explicit LambdaTask(OnRunType&& aOnRun) : mOnRun(Move(aOnRun)) {}
+private:
+  NS_IMETHOD
+  Run() override
+  {
+    mOnRun();
+    return NS_OK;
+  }
+  OnRunType mOnRun;
+};
+
+template<typename OnRunType>
+already_AddRefed<LambdaTask<OnRunType>>
+NewTaskFrom(OnRunType&& aOnRun)
+{
+  typedef LambdaTask<OnRunType> LambdaType;
+  RefPtr<LambdaType> lambda = new LambdaType(Forward<OnRunType>(aOnRun));
+  return lambda.forget();
+}
+
+} // namespace media
+} // namespace mozilla
+
+#endif // mozilla_MediaTaskUtils_h
diff --git a/dom/media/systemservices/MediaUtils.cpp b/dom/media/systemservices/MediaUtils.cpp
new file mode 100644
index 0000000000..a77e3404ab
--- /dev/null
+++ b/dom/media/systemservices/MediaUtils.cpp
@@ -0,0 +1,15 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaUtils.h"
+
+namespace mozilla {
+namespace media {
+
+NS_IMPL_ISUPPORTS(ShutdownBlocker, nsIAsyncShutdownBlocker)
+
+} // namespace media
+} // namespace mozilla
diff --git a/dom/media/systemservices/MediaUtils.h b/dom/media/systemservices/MediaUtils.h
new file mode 100644
index 0000000000..18f7d3e41a
--- /dev/null
+++ b/dom/media/systemservices/MediaUtils.h
@@ -0,0 +1,373 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_MediaUtils_h
+#define mozilla_MediaUtils_h
+
+#include "nsThreadUtils.h"
+#include "nsIAsyncShutdown.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+namespace media {
+
+/*
+ * media::Pledge - A promise-like pattern for c++ that takes lambda functions.
+ *
+ * Asynchronous APIs that proxy to another thread or to the chrome process and
+ * back may find it useful to return a pledge to callers who then use
+ * pledge.Then(func) to specify a lambda function to be invoked with the result
+ * later back on this same thread.
+ *
+ * Callers will enjoy that lambdas allow "capturing" of local variables, much
+ * like closures in JavaScript (safely by-copy by default).
+ *
+ * Callers will also enjoy that they do not need to be thread-safe (their code
+ * runs on the same thread after all).
+ *
+ * Advantageously, pledges are non-threadsafe by design (because locking and
+ * event queues are redundant). This means none of the lambdas you pass in,
+ * or variables you lambda-capture into them, need be threasafe or support
+ * threadsafe refcounting. After all, they'll run later on the same thread.
+ *
+ *   RefPtr<media::Pledge<Foo>> p = GetFooAsynchronously(); // returns a pledge
+ *   p->Then([](const Foo& foo) {
+ *     // use foo here (same thread. Need not be thread-safe!)
+ *   });
+ *
+ * See media::CoatCheck below for an example of GetFooAsynchronously().
+ */
+
+class PledgeBase
+{
+public:
+  NS_INLINE_DECL_REFCOUNTING(PledgeBase);
+protected:
+  virtual ~PledgeBase() {};
+};
+
+template<typename ValueType, typename ErrorType = nsresult>
+class Pledge : public PledgeBase
+{
+  // TODO: Remove workaround once mozilla allows std::function from <functional>
+  // wo/std::function support, do template + virtual trick to accept lambdas
+  class FunctorsBase
+  {
+  public:
+    FunctorsBase() {}
+    virtual void Succeed(ValueType& result) = 0;
+    virtual void Fail(ErrorType& error) = 0;
+    virtual ~FunctorsBase() {};
+  };
+
+public:
+  explicit Pledge() : mDone(false), mRejected(false) {}
+  Pledge(const Pledge& aOther) = delete;
+  Pledge& operator = (const Pledge&) = delete;
+
+  template<typename OnSuccessType>
+  void Then(OnSuccessType&& aOnSuccess)
+  {
+    Then(Forward<OnSuccessType>(aOnSuccess), [](ErrorType&){});
+  }
+
+  template<typename OnSuccessType, typename OnFailureType>
+  void Then(OnSuccessType&& aOnSuccess, OnFailureType&& aOnFailure)
+  {
+    class Functors : public FunctorsBase
+    {
+    public:
+      Functors(OnSuccessType&& aOnSuccessRef, OnFailureType&& aOnFailureRef)
+        : mOnSuccess(Move(aOnSuccessRef)), mOnFailure(Move(aOnFailureRef)) {}
+
+      void Succeed(ValueType& result)
+      {
+        mOnSuccess(result);
+      }
+      void Fail(ErrorType& error)
+      {
+        mOnFailure(error);
+      };
+
+      OnSuccessType mOnSuccess;
+      OnFailureType mOnFailure;
+    };
+    mFunctors = MakeUnique<Functors>(Forward<OnSuccessType>(aOnSuccess),
+                                     Forward<OnFailureType>(aOnFailure));
+    if (mDone) {
+      if (!mRejected) {
+        mFunctors->Succeed(mValue);
+      } else {
+        mFunctors->Fail(mError);
+      }
+    }
+  }
+
+  void Resolve(const ValueType& aValue)
+  {
+    mValue = aValue;
+    Resolve();
+  }
+
+  void Reject(ErrorType rv)
+  {
+    if (!mDone) {
+      mDone = mRejected = true;
+      mError = rv;
+      if (mFunctors) {
+        mFunctors->Fail(mError);
+      }
+    }
+  }
+
+protected:
+  void Resolve()
+  {
+    if (!mDone) {
+      mDone = true;
+      MOZ_ASSERT(!mRejected);
+      if (mFunctors) {
+        mFunctors->Succeed(mValue);
+      }
+    }
+  }
+
+  ValueType mValue;
+private:
+  ~Pledge() {};
+  bool mDone;
+  bool mRejected;
+  ErrorType mError;
+  UniquePtr<FunctorsBase> mFunctors;
+};
+
+/* media::NewRunnableFrom() - Create a Runnable from a lambda.
+ *
+ * Passing variables (closures) to an async function is clunky with Runnable:
+ *
+ *   void Foo()
+ *   {
+ *     class FooRunnable : public Runnable
+ *     {
+ *     public:
+ *       FooRunnable(const Bar &aBar) : mBar(aBar) {}
+ *       NS_IMETHOD Run() override
+ *       {
+ *         // Use mBar
+ *       }
+ *     private:
+ *       RefPtr<Bar> mBar;
+ *     };
+ *
+ *     RefPtr<Bar> bar = new Bar();
+ *     NS_DispatchToMainThread(new FooRunnable(bar);
+ *   }
+ *
+ * It's worse with more variables. Lambdas have a leg up with variable capture:
+ *
+ *   void Foo()
+ *   {
+ *     RefPtr<Bar> bar = new Bar();
+ *     NS_DispatchToMainThread(media::NewRunnableFrom([bar]() mutable {
+ *       // use bar
+ *     });
+ *   }
+ *
+ * Capture is by-copy by default, so the nsRefPtr 'bar' is safely copied for
+ * access on the other thread (threadsafe refcounting in bar is assumed).
+ *
+ * The 'mutable' keyword is only needed for non-const access to bar.
+ */
+
+template<typename OnRunType>
+class LambdaRunnable : public Runnable
+{
+public:
+  explicit LambdaRunnable(OnRunType&& aOnRun) : mOnRun(Move(aOnRun)) {}
+private:
+  NS_IMETHODIMP
+  Run() override
+  {
+    return mOnRun();
+  }
+  OnRunType mOnRun;
+};
+
+template<typename OnRunType>
+already_AddRefed<LambdaRunnable<OnRunType>>
+NewRunnableFrom(OnRunType&& aOnRun)
+{
+  typedef LambdaRunnable<OnRunType> LambdaType;
+  RefPtr<LambdaType> lambda = new LambdaType(Forward<OnRunType>(aOnRun));
+  return lambda.forget();
+}
+
+/* media::CoatCheck - There and back again. Park an object in exchange for an id.
+ *
+ * A common problem with calling asynchronous functions that do work on other
+ * threads or processes is how to pass in a heap object for use once the
+ * function completes, without requiring that object to have threadsafe
+ * refcounting, contain mutexes, be marshaled, or leak if things fail
+ * (or worse, intermittent use-after-free because of lifetime issues).
+ *
+ * One solution is to set up a coat-check on the caller side, park your object
+ * in exchange for an id, and send the id. Common in IPC, but equally useful
+ * for same-process thread-hops, because by never leaving the thread there's
+ * no need for objects to be threadsafe or use threadsafe refcounting. E.g.
+ *
+ *   class FooDoer
+ *   {
+ *     CoatCheck<Foo> mOutstandingFoos;
+ *
+ *   public:
+ *     void DoFoo()
+ *     {
+ *       RefPtr<Foo> foo = new Foo();
+ *       uint32_t requestId = mOutstandingFoos.Append(*foo);
+ *       sChild->SendFoo(requestId);
+ *     }
+ *
+ *     void RecvFooResponse(uint32_t requestId)
+ *     {
+ *       RefPtr<Foo> foo = mOutstandingFoos.Remove(requestId);
+ *       if (foo) {
+ *         // use foo
+ *       }
+ *     }
+ *   };
+ *
+ * If you read media::Pledge earlier, here's how this is useful for pledges:
+ *
+ *   class FooGetter
+ *   {
+ *     CoatCheck<Pledge<Foo>> mOutstandingPledges;
+ *
+ *   public:
+ *     already_addRefed<Pledge<Foo>> GetFooAsynchronously()
+ *     {
+ *       RefPtr<Pledge<Foo>> p = new Pledge<Foo>();
+ *       uint32_t requestId = mOutstandingPledges.Append(*p);
+ *       sChild->SendFoo(requestId);
+ *       return p.forget();
+ *     }
+ *
+ *     void RecvFooResponse(uint32_t requestId, const Foo& fooResult)
+ *     {
+ *       RefPtr<Foo> p = mOutstandingPledges.Remove(requestId);
+ *       if (p) {
+ *         p->Resolve(fooResult);
+ *       }
+ *     }
+ *   };
+ *
+ * This helper is currently optimized for very small sets (i.e. not optimized).
+ * It is also not thread-safe as the whole point is to stay on the same thread.
+ */
+
+template<class T>
+class CoatCheck
+{
+public:
+  typedef std::pair<uint32_t, RefPtr<T>> Element;
+
+  uint32_t Append(T& t)
+  {
+    uint32_t id = GetNextId();
+    mElements.AppendElement(Element(id, RefPtr<T>(&t)));
+    return id;
+  }
+
+  already_AddRefed<T> Remove(uint32_t aId)
+  {
+    for (auto& element : mElements) {
+      if (element.first == aId) {
+        RefPtr<T> ref;
+        ref.swap(element.second);
+        mElements.RemoveElement(element);
+        return ref.forget();
+      }
+    }
+    MOZ_ASSERT_UNREACHABLE("Received id with no matching parked object!");
+    return nullptr;
+  }
+
+private:
+  static uint32_t GetNextId()
+  {
+    static uint32_t counter = 0;
+    return ++counter;
+  };
+  AutoTArray<Element, 3> mElements;
+};
+
+/* media::Refcountable - Add threadsafe ref-counting to something that isn't.
+ *
+ * Often, reference counting is the most practical way to share an object with
+ * another thread without imposing lifetime restrictions, even if there's
+ * otherwise no concurrent access happening on the object.  For instance, an
+ * algorithm on another thread may find it more expedient to modify a passed-in
+ * object, rather than pass expensive copies back and forth.
+ *
+ * Lists in particular often aren't ref-countable, yet are expensive to copy,
+ * e.g. nsTArray<RefPtr<Foo>>. Refcountable can be used to make such objects
+ * (or owning smart-pointers to such objects) refcountable.
+ *
+ * Technical limitation: A template specialization is needed for types that take
+ * a constructor. Please add below (UniquePtr covers a lot of ground though).
+ */
+
+template<typename T>
+class Refcountable : public T
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(Refcountable<T>)
+private:
+  ~Refcountable<T>() {}
+};
+
+template<typename T>
+class Refcountable<UniquePtr<T>> : public UniquePtr<T>
+{
+public:
+  explicit Refcountable<UniquePtr<T>>(T* aPtr) : UniquePtr<T>(aPtr) {}
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(Refcountable<T>)
+private:
+  ~Refcountable<UniquePtr<T>>() {}
+};
+
+/* media::ShutdownBlocker - Async shutdown helper.
+ */
+
+class ShutdownBlocker : public nsIAsyncShutdownBlocker
+{
+public:
+  ShutdownBlocker(const nsString& aName) : mName(aName) {}
+
+  NS_IMETHOD
+  BlockShutdown(nsIAsyncShutdownClient* aProfileBeforeChange) override = 0;
+
+  NS_IMETHOD GetName(nsAString& aName) override
+  {
+    aName = mName;
+    return NS_OK;
+  }
+
+  NS_IMETHOD GetState(nsIPropertyBag**) override
+  {
+    return NS_OK;
+  }
+
+  NS_DECL_ISUPPORTS
+protected:
+  virtual ~ShutdownBlocker() {}
+private:
+  const nsString mName;
+};
+
+} // namespace media
+} // namespace mozilla
+
+#endif // mozilla_MediaUtils_h
diff --git a/dom/media/systemservices/OSXRunLoopSingleton.cpp b/dom/media/systemservices/OSXRunLoopSingleton.cpp
new file mode 100644
index 0000000000..6211d5c127
--- /dev/null
+++ b/dom/media/systemservices/OSXRunLoopSingleton.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OSXRunLoopSingleton.h"
+#include <mozilla/StaticMutex.h>
+
+#include <AudioUnit/AudioUnit.h>
+#include <CoreAudio/AudioHardware.h>
+#include <CoreAudio/HostTime.h>
+#include <CoreFoundation/CoreFoundation.h>
+
+static bool gRunLoopSet = false;
+static mozilla::StaticMutex gMutex;
+
+void mozilla_set_coreaudio_notification_runloop_if_needed()
+{
+  mozilla::StaticMutexAutoLock lock(gMutex);
+  if (gRunLoopSet) {
+    return;
+  }
+
+  /* This is needed so that AudioUnit listeners get called on this thread, and
+   * not the main thread. If we don't do that, they are not called, or a crash
+   * occur, depending on the OSX version. */
+  AudioObjectPropertyAddress runloop_address = {
+    kAudioHardwarePropertyRunLoop,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+  };
+
+  CFRunLoopRef run_loop = nullptr;
+
+  OSStatus r;
+  r = AudioObjectSetPropertyData(kAudioObjectSystemObject,
+                                 &runloop_address,
+                                 0, NULL, sizeof(CFRunLoopRef), &run_loop);
+  if (r != noErr) {
+    NS_WARNING("Could not make global CoreAudio notifications use their own thread.");
+  }
+
+  gRunLoopSet = true;
+}
diff --git a/dom/media/systemservices/OSXRunLoopSingleton.h b/dom/media/systemservices/OSXRunLoopSingleton.h
new file mode 100644
index 0000000000..d06365e146
--- /dev/null
+++ b/dom/media/systemservices/OSXRunLoopSingleton.h
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef OSXRUNLOOPSINGLETON_H_
+#define OSXRUNLOOPSINGLETON_H_
+
+#include <mozilla/Types.h>
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+/* This function tells CoreAudio to use its own thread for device change
+ * notifications, and can be called from any thread without external
+ * synchronization. */
+void MOZ_EXPORT
+mozilla_set_coreaudio_notification_runloop_if_needed();
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif // OSXRUNLOOPSINGLETON_H_
diff --git a/dom/media/systemservices/OpenSLESProvider.cpp b/dom/media/systemservices/OpenSLESProvider.cpp
new file mode 100644
index 0000000000..c7348afa0b
--- /dev/null
+++ b/dom/media/systemservices/OpenSLESProvider.cpp
@@ -0,0 +1,189 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OpenSLESProvider.h"
+#include "mozilla/Logging.h"
+#include "nsDebug.h"
+
+#include <dlfcn.h>
+#include <SLES/OpenSLES_Android.h>
+#include <SLES/OpenSLES_AndroidConfiguration.h>
+
+// MOZ_LOG=OpenSLESProvider:5
+#undef LOG
+#undef LOG_ENABLED
+mozilla::LazyLogModule gOpenSLESProviderLog("OpenSLESProvider");
+#define LOG(args) MOZ_LOG(gOpenSLESProviderLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gOpenSLESProviderLog, mozilla::LogLevel::Debug)
+
+namespace mozilla {
+
+OpenSLESProvider::OpenSLESProvider()
+  : mLock("OpenSLESProvider.mLock"),
+    mSLEngine(nullptr),
+    mSLEngineUsers(0),
+    mIsRealized(false),
+    mOpenSLESLib(nullptr)
+{
+  LOG(("OpenSLESProvider being initialized"));
+}
+
+OpenSLESProvider::~OpenSLESProvider()
+{
+  if (mOpenSLESLib) {
+    LOG(("OpenSLES Engine was not properly Destroyed"));
+    (void)dlclose(mOpenSLESLib);
+  }
+}
+
+/* static */
+OpenSLESProvider& OpenSLESProvider::getInstance()
+{
+  // This doesn't need a Mutex in C++11 or GCC 4.3+, see N2660 and
+  // https://gcc.gnu.org/projects/cxx0x.html
+  static OpenSLESProvider instance;
+  return instance;
+}
+
+/* static */
+SLresult OpenSLESProvider::Get(SLObjectItf * aObjectm,
+                               SLuint32 aOptionCount,
+                               const SLEngineOption *aOptions)
+{
+  OpenSLESProvider& provider = OpenSLESProvider::getInstance();
+  return provider.GetEngine(aObjectm, aOptionCount, aOptions);
+}
+
+SLresult OpenSLESProvider::GetEngine(SLObjectItf * aObjectm,
+                                     SLuint32 aOptionCount,
+                                     const SLEngineOption *aOptions)
+{
+  MutexAutoLock lock(mLock);
+  LOG(("Getting OpenSLES engine"));
+  // Bug 1042051: Validate options are the same
+  if (mSLEngine != nullptr) {
+    *aObjectm = mSLEngine;
+    mSLEngineUsers++;
+    LOG(("Returning existing engine, %d users", mSLEngineUsers));
+    return SL_RESULT_SUCCESS;
+  } else {
+    int res = ConstructEngine(aObjectm, aOptionCount, aOptions);
+    if (res == SL_RESULT_SUCCESS) {
+      // Bug 1042051: Store engine options
+      mSLEngine = *aObjectm;
+      mSLEngineUsers++;
+      LOG(("Returning new engine"));
+    } else {
+      LOG(("Error getting engine: %d", res));
+    }
+    return res;
+  }
+}
+
+SLresult OpenSLESProvider::ConstructEngine(SLObjectItf * aObjectm,
+                                           SLuint32 aOptionCount,
+                                           const SLEngineOption *aOptions)
+{
+  mLock.AssertCurrentThreadOwns();
+
+  if (!mOpenSLESLib) {
+    mOpenSLESLib = dlopen("libOpenSLES.so", RTLD_LAZY);
+    if (!mOpenSLESLib) {
+      LOG(("Failed to dlopen OpenSLES library"));
+      return SL_RESULT_MEMORY_FAILURE;
+    }
+  }
+
+  typedef SLresult (*slCreateEngine_t)(SLObjectItf *,
+                                       SLuint32,
+                                       const SLEngineOption *,
+                                       SLuint32,
+                                       const SLInterfaceID *,
+                                       const SLboolean *);
+
+  slCreateEngine_t f_slCreateEngine =
+    (slCreateEngine_t)dlsym(mOpenSLESLib, "slCreateEngine");
+  int result = f_slCreateEngine(aObjectm, aOptionCount, aOptions, 0, NULL, NULL);
+  return result;
+}
+
+/* static */
+void OpenSLESProvider::Destroy(SLObjectItf * aObjectm)
+{
+  OpenSLESProvider& provider = OpenSLESProvider::getInstance();
+  provider.DestroyEngine(aObjectm);
+}
+
+void OpenSLESProvider::DestroyEngine(SLObjectItf * aObjectm)
+{
+  MutexAutoLock lock(mLock);
+  NS_ASSERTION(mOpenSLESLib, "OpenSLES destroy called but library is not open");
+
+  mSLEngineUsers--;
+  LOG(("Freeing engine, %d users left", mSLEngineUsers));
+  if (mSLEngineUsers) {
+    return;
+  }
+
+  (*(*aObjectm))->Destroy(*aObjectm);
+  // This assumes SLObjectItf is a pointer, but given the previous line,
+  // that's a given.
+  *aObjectm = nullptr;
+
+  (void)dlclose(mOpenSLESLib);
+  mOpenSLESLib = nullptr;
+  mIsRealized = false;
+}
+
+/* static */
+SLresult OpenSLESProvider::Realize(SLObjectItf aObjectm)
+{
+  OpenSLESProvider& provider = OpenSLESProvider::getInstance();
+  return provider.RealizeEngine(aObjectm);
+}
+
+SLresult OpenSLESProvider::RealizeEngine(SLObjectItf aObjectm)
+{
+  MutexAutoLock lock(mLock);
+  NS_ASSERTION(mOpenSLESLib, "OpenSLES realize called but library is not open");
+  NS_ASSERTION(aObjectm != nullptr, "OpenSLES realize engine with empty ObjectItf");
+
+  if (mIsRealized) {
+    LOG(("Not realizing already realized engine"));
+    return SL_RESULT_SUCCESS;
+  } else {
+    SLresult res = (*aObjectm)->Realize(aObjectm, SL_BOOLEAN_FALSE);
+    if (res != SL_RESULT_SUCCESS) {
+      LOG(("Error realizing OpenSLES engine: %d", res));
+    } else {
+      LOG(("Realized OpenSLES engine"));
+      mIsRealized = true;
+    }
+    return res;
+  }
+}
+
+} // namespace mozilla
+
+extern "C" {
+SLresult mozilla_get_sles_engine(SLObjectItf * aObjectm,
+                                 SLuint32 aOptionCount,
+                                 const SLEngineOption *aOptions)
+{
+  return mozilla::OpenSLESProvider::Get(aObjectm, aOptionCount, aOptions);
+}
+
+void mozilla_destroy_sles_engine(SLObjectItf * aObjectm)
+{
+  mozilla::OpenSLESProvider::Destroy(aObjectm);
+}
+
+SLresult mozilla_realize_sles_engine(SLObjectItf aObjectm)
+{
+  return mozilla::OpenSLESProvider::Realize(aObjectm);
+}
+
+}
+
diff --git a/dom/media/systemservices/OpenSLESProvider.h b/dom/media/systemservices/OpenSLESProvider.h
new file mode 100644
index 0000000000..6253e9519e
--- /dev/null
+++ b/dom/media/systemservices/OpenSLESProvider.h
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef _OPENSLESPROVIDER_H_
+#define _OPENSLESPROVIDER_H_
+
+#include <SLES/OpenSLES.h>
+#include <mozilla/Types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+extern MOZ_EXPORT
+SLresult mozilla_get_sles_engine(SLObjectItf * aObjectm,
+                                 SLuint32 aOptionCount,
+                                 const SLEngineOption *aOptions);
+extern MOZ_EXPORT
+void mozilla_destroy_sles_engine(SLObjectItf * aObjectm);
+/* Realize is always in synchronous mode. */
+extern MOZ_EXPORT
+SLresult mozilla_realize_sles_engine(SLObjectItf aObjectm);
+#ifdef __cplusplus
+}
+#endif
+
+#ifdef __cplusplus
+#include "mozilla/Mutex.h"
+
+extern mozilla::LazyLogModule gOpenSLESProviderLog;
+
+namespace mozilla {
+
+class OpenSLESProvider {
+public:
+    static SLresult Get(SLObjectItf * aObjectm,
+                   SLuint32 aOptionCount,
+                   const SLEngineOption *aOptions);
+    static void Destroy(SLObjectItf * aObjectm);
+    static SLresult Realize(SLObjectItf aObjectm);
+private:
+    OpenSLESProvider();
+    ~OpenSLESProvider();
+    OpenSLESProvider(OpenSLESProvider const&); // NO IMPLEMENTATION
+    void operator=(OpenSLESProvider const&);   // NO IMPLEMENTATION
+    static OpenSLESProvider& getInstance();
+    SLresult GetEngine(SLObjectItf * aObjectm,
+                       SLuint32 aOptionCount,
+                       const SLEngineOption *aOptions);
+    SLresult ConstructEngine(SLObjectItf * aObjectm,
+                             SLuint32 aOptionCount,
+                             const SLEngineOption *aOptions);
+    SLresult RealizeEngine(SLObjectItf aObjectm);
+    void DestroyEngine(SLObjectItf * aObjectm);
+
+    // Protect all our internal variables
+    mozilla::Mutex mLock;
+    SLObjectItf mSLEngine;
+    int mSLEngineUsers;
+    bool mIsRealized;
+    void *mOpenSLESLib;
+};
+
+} //namespace
+#endif // cplusplus
+
+#endif /* _OPENSLESPROVIDER_H_ */
diff --git a/dom/media/systemservices/PCameras.ipdl b/dom/media/systemservices/PCameras.ipdl
new file mode 100644
index 0000000000..b9fa583295
--- /dev/null
+++ b/dom/media/systemservices/PCameras.ipdl
@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PContent;
+include protocol PBackground;
+
+using mozilla::camera::CaptureEngine from "mozilla/media/CamerasTypes.h";
+
+namespace mozilla {
+namespace camera {
+
+struct CaptureCapability
+{
+  int width;
+  int height;
+  int maxFPS;
+  int expectedCaptureDelay;
+  int rawType;
+  int codecType;
+  bool interlaced;
+};
+
+async protocol PCameras
+{
+  manager PBackground;
+
+child:
+  async FrameSizeChange(CaptureEngine capEngine, int cap_id, int w, int h);
+  // transfers ownership of |buffer| from parent to child
+  async DeliverFrame(CaptureEngine capEngine, int cap_id,
+                     Shmem buffer, size_t size, uint32_t time_stamp,
+                     int64_t ntp_time, int64_t render_time);
+  async DeviceChange();
+  async ReplyNumberOfCaptureDevices(int numdev);
+  async ReplyNumberOfCapabilities(int numdev);
+  async ReplyAllocateCaptureDevice(int numdev);
+  async ReplyGetCaptureCapability(CaptureCapability cap);
+  async ReplyGetCaptureDevice(nsCString device_name, nsCString device_id, bool scary);
+  async ReplyFailure();
+  async ReplySuccess();
+  async __delete__();
+
+parent:
+  async NumberOfCaptureDevices(CaptureEngine engine);
+  async NumberOfCapabilities(CaptureEngine engine, nsCString deviceUniqueIdUTF8);
+
+  async GetCaptureCapability(CaptureEngine engine, nsCString unique_idUTF8, int capability_number);
+  async GetCaptureDevice(CaptureEngine engine, int num);
+
+  async AllocateCaptureDevice(CaptureEngine engine, nsCString unique_idUTF8, nsCString origin);
+  async ReleaseCaptureDevice(CaptureEngine engine, int numdev);
+  async StartCapture(CaptureEngine engine, int numdev, CaptureCapability capability);
+  async StopCapture(CaptureEngine engine, int numdev);
+  // transfers frame back
+  async ReleaseFrame(Shmem s);
+
+  // Ask parent to delete us
+  async AllDone();
+  // setup camera engine
+  async EnsureInitialized(CaptureEngine engine);
+};
+
+} // namespace camera
+} // namespace mozilla
diff --git a/dom/media/systemservices/PMedia.ipdl b/dom/media/systemservices/PMedia.ipdl
new file mode 100644
index 0000000000..c060f030eb
--- /dev/null
+++ b/dom/media/systemservices/PMedia.ipdl
@@ -0,0 +1,51 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PContent;
+
+namespace mozilla {
+namespace media {
+
+protocol PMedia
+{
+  manager PContent;
+
+parent:
+  /**
+   * Requests a potentially persistent unique secret key for each origin.
+   * Has no expiry, but is cleared by age along with cookies.
+   * This is needed by mediaDevices.enumerateDevices() to produce persistent
+   * deviceIds that wont work cross-origin.
+   *
+   * If aPrivateBrowsing is false, a key for this origin is returned from a
+   * primary pool of temporal in-memory keys and persistent keys read from disk.
+   * If no key exists, a temporal one is created.
+   * If aPersist is true and key is temporal, the key is promoted to persistent.
+   * Once persistent, a key cannot become temporal again.
+   *
+   * If aPrivateBrowsing is true, a different key for this origin is returned
+   * from a secondary pool that is never persisted to disk, and aPersist is
+   * ignored.
+   */
+  async GetOriginKey(uint32_t aRequestId, nsCString aOrigin, bool aPrivateBrowsing,
+                     bool aPersist);
+
+  /**
+   * Clear per-orgin list of persistent deviceIds stored for enumerateDevices
+   * Fire and forget.
+   *
+   * aSinceTime - milliseconds since 1 January 1970 00:00:00 UTC. 0 = clear all
+   *
+   * aOnlyPrivateBrowsing - if true then only purge the separate in-memory
+   *                        per-origin list used in Private Browsing.
+   */
+  async SanitizeOriginKeys(uint64_t aSinceWhen, bool aOnlyPrivateBrowsing);
+
+child:
+  async GetOriginKeyResponse(uint32_t aRequestId, nsCString key);
+  async __delete__();
+};
+
+} // namespace media
+} // namespace mozilla
diff --git a/dom/media/systemservices/PMediaSystemResourceManager.ipdl b/dom/media/systemservices/PMediaSystemResourceManager.ipdl
new file mode 100644
index 0000000000..8ba5467656
--- /dev/null
+++ b/dom/media/systemservices/PMediaSystemResourceManager.ipdl
@@ -0,0 +1,37 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+include protocol PImageBridge;
+include "mozilla/media/MediaSystemResourceMessageUtils.h";
+
+using mozilla::MediaSystemResourceType from "mozilla/media/MediaSystemResourceTypes.h";
+
+namespace mozilla {
+namespace media {
+
+/*
+ * The PMediaSystemResourceManager is a sub-protocol in PImageBridge
+ */
+sync protocol PMediaSystemResourceManager
+{
+  manager PImageBridge;
+
+child:
+  async Response(uint32_t aId, bool aSuccess);
+  async __delete__();
+
+parent:
+  async Acquire(uint32_t aId, MediaSystemResourceType aResourceType, bool aWillWait);
+  async Release(uint32_t aId);
+
+  /**
+   * Asynchronously tell the parent side to remove the PMediaSystemResourceManager.
+   */
+  async RemoveResourceManager();
+};
+
+} // namespace media
+} // namespace mozilla
+
diff --git a/dom/media/systemservices/ShmemPool.cpp b/dom/media/systemservices/ShmemPool.cpp
new file mode 100644
index 0000000000..334a94e35c
--- /dev/null
+++ b/dom/media/systemservices/ShmemPool.cpp
@@ -0,0 +1,82 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Logging.h"
+#include "mozilla/ShmemPool.h"
+#include "mozilla/Move.h"
+
+namespace mozilla {
+
+ShmemPool::ShmemPool(size_t aPoolSize)
+  : mMutex("mozilla::ShmemPool"),
+    mPoolFree(aPoolSize)
+#ifdef DEBUG
+    ,mMaxPoolUse(0)
+#endif
+{
+  mShmemPool.SetLength(aPoolSize);
+}
+
+mozilla::ShmemBuffer ShmemPool::GetIfAvailable(size_t aSize)
+{
+  MutexAutoLock lock(mMutex);
+
+  // Pool is empty, don't block caller.
+  if (mPoolFree == 0) {
+    // This isn't initialized, so will be understood as an error.
+    return ShmemBuffer();
+  }
+
+  ShmemBuffer& res = mShmemPool[mPoolFree - 1];
+
+  if (!res.mInitialized) {
+    LOG(("No free preallocated Shmem"));
+    return ShmemBuffer();
+  }
+
+  MOZ_ASSERT(res.mShmem.IsWritable(), "Pool in Shmem is not writable?");
+
+  if (res.mShmem.Size<char>() < aSize) {
+    LOG(("Free Shmem but not of the right size"));
+    return ShmemBuffer();
+  }
+
+  mPoolFree--;
+#ifdef DEBUG
+  size_t poolUse = mShmemPool.Length() - mPoolFree;
+  if (poolUse > mMaxPoolUse) {
+    mMaxPoolUse = poolUse;
+    LOG(("Maximum ShmemPool use increased: %d buffers", mMaxPoolUse));
+  }
+#endif
+  return Move(res);
+}
+
+void ShmemPool::Put(ShmemBuffer&& aShmem)
+{
+  MutexAutoLock lock(mMutex);
+  MOZ_ASSERT(mPoolFree < mShmemPool.Length());
+  mShmemPool[mPoolFree] = Move(aShmem);
+  mPoolFree++;
+#ifdef DEBUG
+  size_t poolUse = mShmemPool.Length() - mPoolFree;
+  if (poolUse > 0) {
+    LOG(("ShmemPool usage reduced to %d buffers", poolUse));
+  }
+#endif
+}
+
+ShmemPool::~ShmemPool()
+{
+#ifdef DEBUG
+  for (size_t i = 0; i < mShmemPool.Length(); i++) {
+    MOZ_ASSERT(!mShmemPool[i].Valid());
+  }
+#endif
+}
+
+} // namespace mozilla
diff --git a/dom/media/systemservices/ShmemPool.h b/dom/media/systemservices/ShmemPool.h
new file mode 100644
index 0000000000..95901ffa02
--- /dev/null
+++ b/dom/media/systemservices/ShmemPool.h
@@ -0,0 +1,153 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set sw=2 ts=8 et ft=cpp : */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_ShmemPool_h
+#define mozilla_ShmemPool_h
+
+#include "mozilla/ipc/Shmem.h"
+#include "mozilla/Mutex.h"
+
+#undef LOG
+#undef LOG_ENABLED
+extern mozilla::LazyLogModule gCamerasParentLog;
+#define LOG(args) MOZ_LOG(gCamerasParentLog, mozilla::LogLevel::Debug, args)
+#define LOG_ENABLED() MOZ_LOG_TEST(gCamerasParentLog, mozilla::LogLevel::Debug)
+
+namespace mozilla {
+
+class ShmemPool;
+
+class ShmemBuffer {
+public:
+  ShmemBuffer() : mInitialized(false) {}
+  explicit ShmemBuffer(mozilla::ipc::Shmem aShmem) {
+    mInitialized = true;
+    mShmem = aShmem;
+  }
+
+  ShmemBuffer(ShmemBuffer&& rhs) {
+    mInitialized = rhs.mInitialized;
+    mShmem = Move(rhs.mShmem);
+  }
+
+  ShmemBuffer& operator=(ShmemBuffer&& rhs) {
+    MOZ_ASSERT(&rhs != this, "self-moves are prohibited");
+    mInitialized = rhs.mInitialized;
+    mShmem = Move(rhs.mShmem);
+    return *this;
+  }
+
+  // No copies allowed
+  ShmemBuffer(const ShmemBuffer&) = delete;
+  ShmemBuffer& operator=(const ShmemBuffer&) = delete;
+
+  bool Valid() {
+    return mInitialized;
+  }
+
+  char* GetBytes() {
+    return mShmem.get<char>();
+  }
+
+  mozilla::ipc::Shmem& Get() {
+    return mShmem;
+  }
+
+private:
+  friend class ShmemPool;
+
+  bool mInitialized;
+  mozilla::ipc::Shmem mShmem;
+};
+
+class ShmemPool {
+public:
+  explicit ShmemPool(size_t aPoolSize);
+  ~ShmemPool();
+  // Get/GetIfAvailable differ in what thread they can run on. GetIfAvailable
+  // can run anywhere but won't allocate if the right size isn't available.
+  ShmemBuffer GetIfAvailable(size_t aSize);
+  void Put(ShmemBuffer&& aShmem);
+
+  // We need to use the allocation/deallocation functions
+  // of a specific IPC child/parent instance.
+  template <class T>
+  void Cleanup(T* aInstance)
+  {
+    MutexAutoLock lock(mMutex);
+    for (size_t i = 0; i < mShmemPool.Length(); i++) {
+      if (mShmemPool[i].mInitialized) {
+        aInstance->DeallocShmem(mShmemPool[i].Get());
+        mShmemPool[i].mInitialized = false;
+      }
+    }
+  }
+
+  template <class T>
+  ShmemBuffer Get(T* aInstance, size_t aSize)
+  {
+    MutexAutoLock lock(mMutex);
+
+    // Pool is empty, don't block caller.
+    if (mPoolFree == 0) {
+      // This isn't initialized, so will be understood as an error.
+      return ShmemBuffer();
+    }
+
+    ShmemBuffer& res = mShmemPool[mPoolFree - 1];
+
+    if (!res.mInitialized) {
+      LOG(("Initializing new Shmem in pool"));
+      if (!aInstance->AllocShmem(aSize, ipc::SharedMemory::TYPE_BASIC, &res.mShmem)) {
+        LOG(("Failure allocating new Shmem buffer"));
+        return ShmemBuffer();
+      }
+      res.mInitialized = true;
+    }
+
+    MOZ_ASSERT(res.mShmem.IsWritable(), "Shmem in Pool is not writable?");
+
+    // Prepare buffer, increase size if needed (we never shrink as we don't
+    // maintain seperate sized pools and we don't want to keep reallocating)
+    if (res.mShmem.Size<char>() < aSize) {
+      LOG(("Size change/increase in Shmem Pool"));
+      aInstance->DeallocShmem(res.mShmem);
+      res.mInitialized = false;
+      // this may fail; always check return value
+      if (!aInstance->AllocShmem(aSize, ipc::SharedMemory::TYPE_BASIC, &res.mShmem)) {
+        LOG(("Failure allocating resized Shmem buffer"));
+        return ShmemBuffer();
+      } else {
+        res.mInitialized = true;
+      }
+    }
+
+    MOZ_ASSERT(res.mShmem.IsWritable(), "Shmem in Pool is not writable post resize?");
+
+    mPoolFree--;
+#ifdef DEBUG
+    size_t poolUse = mShmemPool.Length() - mPoolFree;
+    if (poolUse > mMaxPoolUse) {
+      mMaxPoolUse = poolUse;
+      LOG(("Maximum ShmemPool use increased: %d buffers", mMaxPoolUse));
+    }
+#endif
+    return Move(res);
+  }
+
+private:
+  Mutex mMutex;
+  size_t mPoolFree;
+#ifdef DEBUG
+  size_t mMaxPoolUse;
+#endif
+  nsTArray<ShmemBuffer> mShmemPool;
+};
+
+
+} // namespace mozilla
+
+#endif  // mozilla_ShmemPool_h
diff --git a/dom/media/systemservices/moz.build b/dom/media/systemservices/moz.build
new file mode 100644
index 0000000000..33e5ed1f17
--- /dev/null
+++ b/dom/media/systemservices/moz.build
@@ -0,0 +1,104 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if CONFIG['MOZ_WEBRTC']:
+    EXPORTS += [
+        'CamerasChild.h',
+        'CamerasParent.h',
+        'LoadManager.h',
+        'LoadManagerFactory.h',
+        'LoadMonitor.h',
+    ]
+    UNIFIED_SOURCES += [
+        'CamerasChild.cpp',
+        'CamerasParent.cpp',
+        'LoadManager.cpp',
+        'LoadManagerFactory.cpp',
+        'LoadMonitor.cpp',
+        'ShmemPool.cpp',
+    ]
+    LOCAL_INCLUDES += [
+        '/media/webrtc/signaling',
+        '/media/webrtc/trunk',
+    ]
+if CONFIG['OS_TARGET'] == 'WINNT':
+    DEFINES['WEBRTC_WIN'] = True
+else:
+    DEFINES['WEBRTC_POSIX'] = True
+
+
+if CONFIG['OS_TARGET'] == 'Android':
+    EXPORTS += [
+        'OpenSLESProvider.h'
+    ]
+    UNIFIED_SOURCES += [
+        'OpenSLESProvider.cpp',
+    ]
+
+if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
+  UNIFIED_SOURCES += ['OSXRunLoopSingleton.cpp']
+  EXPORTS += ['OSXRunLoopSingleton.h']
+
+if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk':
+    if CONFIG['ANDROID_VERSION'] >= '17':
+        LOCAL_INCLUDES += [
+            '%' + '%s/frameworks/wilhelm/include' % CONFIG['ANDROID_SOURCE'],
+        ]
+    else:
+        LOCAL_INCLUDES += [
+            '%' + '%s/system/media/wilhelm/include' % CONFIG['ANDROID_SOURCE'],
+        ]
+
+if CONFIG['_MSC_VER']:
+    DEFINES['__PRETTY_FUNCTION__'] = '__FUNCSIG__'
+
+    # This is intended as a temporary workaround to enable building with VS2015.
+    # media\webrtc\trunk\webrtc/base/criticalsection.h(59): warning C4312:
+    # 'reinterpret_cast': conversion from 'DWORD' to 'HANDLE' of greater size
+    CXXFLAGS += ['-wd4312']
+
+EXPORTS.mozilla += ['ShmemPool.h',]
+
+EXPORTS.mozilla.media += ['CamerasTypes.h',
+                          'DeviceChangeCallback.h',
+                          'MediaChild.h',
+                          'MediaParent.h',
+                          'MediaSystemResourceClient.h',
+                          'MediaSystemResourceManager.h',
+                          'MediaSystemResourceManagerChild.h',
+                          'MediaSystemResourceManagerParent.h',
+                          'MediaSystemResourceMessageUtils.h',
+                          'MediaSystemResourceService.h',
+                          'MediaSystemResourceTypes.h',
+                          'MediaTaskUtils.h',
+                          'MediaUtils.h',
+]
+UNIFIED_SOURCES += [
+    'MediaChild.cpp',
+    'MediaParent.cpp',
+    'MediaSystemResourceClient.cpp',
+    'MediaSystemResourceManager.cpp',
+    'MediaSystemResourceManagerChild.cpp',
+    'MediaSystemResourceManagerParent.cpp',
+    'MediaSystemResourceService.cpp',
+    'MediaUtils.cpp',
+]
+IPDL_SOURCES += [
+    'PCameras.ipdl',
+    'PMedia.ipdl',
+    'PMediaSystemResourceManager.ipdl',
+]
+# /dom/base needed for nsGlobalWindow.h in MediaChild.cpp
+LOCAL_INCLUDES += [
+    '/dom/base',
+]
+
+include('/ipc/chromium/chromium-config.mozbuild')
+
+FINAL_LIBRARY = 'xul'
+
+if CONFIG['GNU_CXX']:
+    CXXFLAGS += ['-Wno-error=shadow']