From e482e335bb8de6630a171cd0a784b420d91106b2 Mon Sep 17 00:00:00 2001
From: "Matt A. Tobin" <email@mattatobin.com>
Date: Fri, 17 Apr 2020 06:14:10 -0400
Subject: Bug 1389743 - Only reconstruct frames synchronously from
 ContentRemoved when called from frame construction

Tag #1375
---
 dom/base/Element.cpp     | 19 +++----------------
 dom/xbl/nsXBLService.cpp | 32 ++------------------------------
 2 files changed, 5 insertions(+), 46 deletions(-)

(limited to 'dom')

diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 31af0c1db4..a2b78092ad 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1112,12 +1112,9 @@ Element::CreateShadowRoot(ErrorResult& aError)
     return nullptr;
   }
 
-  nsIDocument* doc = GetComposedDoc();
-  nsIContent* destroyedFramesFor = nullptr;
-  if (doc) {
-    nsIPresShell* shell = doc->GetShell();
-    if (shell) {
-      shell->DestroyFramesFor(this, &destroyedFramesFor);
+  if (nsIDocument* doc = GetComposedDoc()) {
+    if (nsIPresShell* shell = doc->GetShell()) {
+      shell->DestroyFramesFor(this);
       MOZ_ASSERT(!shell->FrameManager()->GetDisplayContentsStyleFor(this));
     }
   }
@@ -1160,16 +1157,6 @@ Element::CreateShadowRoot(ErrorResult& aError)
 
   SetXBLBinding(xblBinding);
 
-  // Recreate the frame for the bound content because binding a ShadowRoot
-  // changes how things are rendered.
-  if (doc) {
-    MOZ_ASSERT(doc == GetComposedDoc());
-    nsIPresShell* shell = doc->GetShell();
-    if (shell) {
-      shell->CreateFramesFor(destroyedFramesFor);
-    }
-  }
-
   return shadowRoot.forget();
 }
 
diff --git a/dom/xbl/nsXBLService.cpp b/dom/xbl/nsXBLService.cpp
index 3f98eefe0d..ef0d205643 100644
--- a/dom/xbl/nsXBLService.cpp
+++ b/dom/xbl/nsXBLService.cpp
@@ -124,38 +124,10 @@ public:
     // Destroy the frames for mBoundElement. Do this after getting the binding,
     // since if the binding fetch fails then we don't want to destroy the
     // frames.
-    nsIContent* destroyedFramesFor = nullptr;
-    nsIPresShell* shell = doc->GetShell();
-    if (shell) {
-      shell->DestroyFramesFor(mBoundElement, &destroyedFramesFor);
+    if (nsIPresShell* shell = doc->GetShell()) {
+      shell->DestroyFramesFor(mBoundElement->AsElement());
     }
     MOZ_ASSERT(!mBoundElement->GetPrimaryFrame());
-
-    // If |mBoundElement| is (in addition to having binding |mBinding|)
-    // also a descendant of another element with binding |mBinding|,
-    // then we might have just constructed it due to the
-    // notification of its parent.  (We can know about both if the
-    // binding loads were triggered from the DOM rather than frame
-    // construction.)  So we have to check both whether the element
-    // has a primary frame and whether it's in the frame manager maps
-    // before sending a ContentInserted notification, or bad things
-    // will happen.
-    MOZ_ASSERT(shell == doc->GetShell());
-    if (shell) {
-      nsIFrame* childFrame = mBoundElement->GetPrimaryFrame();
-      if (!childFrame) {
-        // Check to see if it's in the undisplayed content map...
-        nsFrameManager* fm = shell->FrameManager();
-        nsStyleContext* sc = fm->GetUndisplayedContent(mBoundElement);
-        if (!sc) {
-          // or in the display:contents map.
-          sc = fm->GetDisplayContentsStyleFor(mBoundElement);
-        }
-        if (!sc) {
-          shell->CreateFramesFor(destroyedFramesFor);
-        }
-      }
-    }
   }
 
   nsXBLBindingRequest(nsIURI* aURI, nsIContent* aBoundElement)
-- 
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