Add m-esr52 at 52.6.0

1 files changed, 2339 insertions, 0 deletions

diff --git a/dom/base/nsINode.h b/dom/base/nsINode.h
new file mode 100644
index 0000000000..d82f5f8990
--- /dev/null
+++ b/dom/base/nsINode.h
@@ -0,0 +1,2339 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 nsINode_h___
+#define nsINode_h___
+
+#include "mozilla/Likely.h"
+#include "mozilla/ServoTypes.h"
+#include "mozilla/UniquePtr.h"
+#include "nsCOMPtr.h"               // for member, local
+#include "nsGkAtoms.h"              // for nsGkAtoms::baseURIProperty
+#include "nsIDOMNode.h"
+#include "mozilla/dom/NodeInfo.h"            // member (in nsCOMPtr)
+#include "nsIVariant.h"             // for use in GetUserData()
+#include "nsNodeInfoManager.h"      // for use in NodePrincipal()
+#include "nsPropertyTable.h"        // for typedefs
+#include "nsTObserverArray.h"       // for member
+#include "mozilla/ErrorResult.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/dom/EventTarget.h" // for base class
+#include "js/TypeDecls.h"     // for Handle, Value, JSObject, JSContext
+#include "mozilla/dom/DOMString.h"
+#include "mozilla/dom/BindingDeclarations.h"
+#include <iosfwd>
+
+// Including 'windows.h' will #define GetClassInfo to something else.
+#ifdef XP_WIN
+#ifdef GetClassInfo
+#undef GetClassInfo
+#endif
+#endif
+
+class nsAttrAndChildArray;
+class nsChildContentList;
+struct nsCSSSelectorList;
+class nsDOMAttributeMap;
+class nsIAnimationObserver;
+class nsIContent;
+class nsIDocument;
+class nsIDOMElement;
+class nsIDOMNodeList;
+class nsIEditor;
+class nsIFrame;
+class nsIMutationObserver;
+class nsINode;
+class nsINodeList;
+class nsIPresShell;
+class nsIPrincipal;
+class nsIURI;
+class nsNodeSupportsWeakRefTearoff;
+class nsNodeWeakReference;
+class nsDOMMutationObserver;
+
+namespace mozilla {
+class EventListenerManager;
+namespace dom {
+/**
+ * @return true if aChar is what the DOM spec defines as 'space character'.
+ * http://dom.spec.whatwg.org/#space-character
+ */
+inline bool IsSpaceCharacter(char16_t aChar) {
+  return aChar == ' ' || aChar == '\t' || aChar == '\n' || aChar == '\r' ||
+         aChar == '\f';
+}
+inline bool IsSpaceCharacter(char aChar) {
+  return aChar == ' ' || aChar == '\t' || aChar == '\n' || aChar == '\r' ||
+         aChar == '\f';
+}
+class AccessibleNode;
+struct BoxQuadOptions;
+struct ConvertCoordinateOptions;
+class DOMPoint;
+class DOMQuad;
+class DOMRectReadOnly;
+class Element;
+class EventHandlerNonNull;
+template<typename T> class Optional;
+class OwningNodeOrString;
+template<typename> class Sequence;
+class Text;
+class TextOrElementOrDocument;
+struct DOMPointInit;
+} // namespace dom
+} // namespace mozilla
+
+#define NODE_FLAG_BIT(n_) \
+  (nsWrapperCache::FlagsType(1U) << (WRAPPER_CACHE_FLAGS_BITS_USED + (n_)))
+
+enum {
+  // This bit will be set if the node has a listener manager.
+  NODE_HAS_LISTENERMANAGER =              NODE_FLAG_BIT(0),
+
+  // Whether this node has had any properties set on it
+  NODE_HAS_PROPERTIES =                   NODE_FLAG_BIT(1),
+
+  // Whether this node is the root of an anonymous subtree.  Note that this
+  // need not be a native anonymous subtree.  Any anonymous subtree, including
+  // XBL-generated ones, will do.  This flag is set-once: once a node has it,
+  // it must not be removed.
+  // NOTE: Should only be used on nsIContent nodes
+  NODE_IS_ANONYMOUS_ROOT =                NODE_FLAG_BIT(2),
+
+  // Whether the node has some ancestor, possibly itself, that is native
+  // anonymous.  This includes ancestors crossing XBL scopes, in cases when an
+  // XBL binding is attached to an element which has a native anonymous
+  // ancestor.  This flag is set-once: once a node has it, it must not be
+  // removed.
+  // NOTE: Should only be used on nsIContent nodes
+  NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE =          NODE_FLAG_BIT(3),
+
+  // Whether this node is the root of a native anonymous (from the perspective
+  // of its parent) subtree.  This flag is set-once: once a node has it, it
+  // must not be removed.
+  // NOTE: Should only be used on nsIContent nodes
+  NODE_IS_NATIVE_ANONYMOUS_ROOT =         NODE_FLAG_BIT(4),
+
+  // Forces the XBL code to treat this node as if it were
+  // in the document and therefore should get bindings attached.
+  NODE_FORCE_XBL_BINDINGS =               NODE_FLAG_BIT(5),
+
+  // Whether a binding manager may have a pointer to this
+  NODE_MAY_BE_IN_BINDING_MNGR =           NODE_FLAG_BIT(6),
+
+  NODE_IS_EDITABLE =                      NODE_FLAG_BIT(7),
+
+  // For all Element nodes, NODE_MAY_HAVE_CLASS is guaranteed to be set if the
+  // node in fact has a class, but may be set even if it doesn't.
+  NODE_MAY_HAVE_CLASS =                   NODE_FLAG_BIT(8),
+
+  // Whether the node participates in a shadow tree.
+  NODE_IS_IN_SHADOW_TREE =                NODE_FLAG_BIT(9),
+
+  // Node has an :empty or :-moz-only-whitespace selector
+  NODE_HAS_EMPTY_SELECTOR =               NODE_FLAG_BIT(10),
+
+  // A child of the node has a selector such that any insertion,
+  // removal, or appending of children requires restyling the parent.
+  NODE_HAS_SLOW_SELECTOR =                NODE_FLAG_BIT(11),
+
+  // A child of the node has a :first-child, :-moz-first-node,
+  // :only-child, :last-child or :-moz-last-node selector.
+  NODE_HAS_EDGE_CHILD_SELECTOR =          NODE_FLAG_BIT(12),
+
+  // A child of the node has a selector such that any insertion or
+  // removal of children requires restyling later siblings of that
+  // element.  Additionally (in this manner it is stronger than
+  // NODE_HAS_SLOW_SELECTOR), if a child's style changes due to any
+  // other content tree changes (e.g., the child changes to or from
+  // matching :empty due to a grandchild insertion or removal), the
+  // child's later siblings must also be restyled.
+  NODE_HAS_SLOW_SELECTOR_LATER_SIBLINGS = NODE_FLAG_BIT(13),
+
+  NODE_ALL_SELECTOR_FLAGS =               NODE_HAS_EMPTY_SELECTOR |
+                                          NODE_HAS_SLOW_SELECTOR |
+                                          NODE_HAS_EDGE_CHILD_SELECTOR |
+                                          NODE_HAS_SLOW_SELECTOR_LATER_SIBLINGS,
+
+  // This node needs to go through frame construction to get a frame (or
+  // undisplayed entry).
+  NODE_NEEDS_FRAME =                      NODE_FLAG_BIT(14),
+
+  // At least one descendant in the flattened tree has NODE_NEEDS_FRAME set.
+  // This should be set on every node on the flattened tree path between the
+  // node(s) with NODE_NEEDS_FRAME and the root content.
+  NODE_DESCENDANTS_NEED_FRAMES =          NODE_FLAG_BIT(15),
+
+  // Set if the node has the accesskey attribute set.
+  NODE_HAS_ACCESSKEY =                    NODE_FLAG_BIT(16),
+
+  // Set if the node has right-to-left directionality
+  NODE_HAS_DIRECTION_RTL =                NODE_FLAG_BIT(17),
+
+  // Set if the node has left-to-right directionality
+  NODE_HAS_DIRECTION_LTR =                NODE_FLAG_BIT(18),
+
+  NODE_ALL_DIRECTION_FLAGS =              NODE_HAS_DIRECTION_LTR |
+                                          NODE_HAS_DIRECTION_RTL,
+
+  NODE_CHROME_ONLY_ACCESS =               NODE_FLAG_BIT(19),
+
+  NODE_IS_ROOT_OF_CHROME_ONLY_ACCESS =    NODE_FLAG_BIT(20),
+
+  // These two bits are shared by Gecko's and Servo's restyle systems for
+  // different purposes. They should not be accessed directly, and access to
+  // them should be properly guarded by asserts.
+  NODE_SHARED_RESTYLE_BIT_1 =             NODE_FLAG_BIT(21),
+  NODE_SHARED_RESTYLE_BIT_2 =             NODE_FLAG_BIT(22),
+
+  // Whether this node is dirty for Servo's style system.
+  NODE_IS_DIRTY_FOR_SERVO =               NODE_SHARED_RESTYLE_BIT_1,
+
+  // Whether this node has dirty descendants for Servo's style system.
+  NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO =  NODE_SHARED_RESTYLE_BIT_2,
+
+  // Remaining bits are node type specific.
+  NODE_TYPE_SPECIFIC_BITS_OFFSET =        23
+};
+
+// Make sure we have space for our bits
+#define ASSERT_NODE_FLAGS_SPACE(n) \
+  static_assert(WRAPPER_CACHE_FLAGS_BITS_USED + (n) <=                          \
+                  sizeof(nsWrapperCache::FlagsType) * 8,                        \
+                "Not enough space for our bits")
+ASSERT_NODE_FLAGS_SPACE(NODE_TYPE_SPECIFIC_BITS_OFFSET);
+
+/**
+ * Class used to detect unexpected mutations. To use the class create an
+ * nsMutationGuard on the stack before unexpected mutations could occur.
+ * You can then at any time call Mutated to check if any unexpected mutations
+ * have occurred.
+ */
+class nsMutationGuard {
+public:
+  nsMutationGuard()
+  {
+    mStartingGeneration = sGeneration;
+  }
+
+  /**
+   * Returns true if any unexpected mutations have occurred. You can pass in
+   * an 8-bit ignore count to ignore a number of expected mutations.
+   *
+   * We don't need to care about overflow because subtraction of uint64_t's is
+   * finding the difference between two elements of the group Z < 2^64.  Once
+   * we know the difference between two elements we only need to check that is
+   * less than the given number of mutations to know less than that many
+   * mutations occured.  Assuming constant 1ns mutations it would take 584
+   * years for sGeneration to fully wrap around so we can ignore a guard living
+   * through a full wrap around.
+   */
+  bool Mutated(uint8_t aIgnoreCount)
+  {
+    return (sGeneration - mStartingGeneration) > aIgnoreCount;
+  }
+
+  // This function should be called whenever a mutation that we want to keep
+  // track of happen. For now this is only done when children are added or
+  // removed, but we might do it for attribute changes too in the future.
+  static void DidMutate()
+  {
+    sGeneration++;
+  }
+
+private:
+  // This is the value sGeneration had when the guard was constructed.
+  uint64_t mStartingGeneration;
+
+  // This value is incremented on every mutation, for the life of the process.
+  static uint64_t sGeneration;
+};
+
+// This should be used for any nsINode sub-class that has fields of its own
+// that it needs to measure;  any sub-class that doesn't use it will inherit
+// SizeOfExcludingThis from its super-class.  SizeOfIncludingThis() need not be
+// defined, it is inherited from nsINode.
+// This macro isn't actually specific to nodes, and bug 956400 will move it into MFBT.
+#define NS_DECL_SIZEOF_EXCLUDING_THIS \
+  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const override;
+
+// Categories of node properties
+// 0 is global.
+#define DOM_USER_DATA         1
+#define SMIL_MAPPED_ATTR_ANIMVAL 2
+
+// IID for the nsINode interface
+#define NS_INODE_IID \
+{ 0x70ba4547, 0x7699, 0x44fc, \
+  { 0xb3, 0x20, 0x52, 0xdb, 0xe3, 0xd1, 0xf9, 0x0a } }
+
+/**
+ * An internal interface that abstracts some DOMNode-related parts that both
+ * nsIContent and nsIDocument share.  An instance of this interface has a list
+ * of nsIContent children and provides access to them.
+ */
+class nsINode : public mozilla::dom::EventTarget
+{
+public:
+  typedef mozilla::dom::BoxQuadOptions BoxQuadOptions;
+  typedef mozilla::dom::ConvertCoordinateOptions ConvertCoordinateOptions;
+  typedef mozilla::dom::DOMPoint DOMPoint;
+  typedef mozilla::dom::DOMPointInit DOMPointInit;
+  typedef mozilla::dom::DOMQuad DOMQuad;
+  typedef mozilla::dom::DOMRectReadOnly DOMRectReadOnly;
+  typedef mozilla::dom::OwningNodeOrString OwningNodeOrString;
+  typedef mozilla::dom::TextOrElementOrDocument TextOrElementOrDocument;
+  typedef mozilla::ErrorResult ErrorResult;
+
+  template<class T>
+  using Sequence = mozilla::dom::Sequence<T>;
+
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_INODE_IID)
+
+  // Among the sub-classes that inherit (directly or indirectly) from nsINode,
+  // measurement of the following members may be added later if DMD finds it is
+  // worthwhile:
+  // - nsGenericHTMLElement:  mForm, mFieldSet
+  // - nsGenericHTMLFrameElement: mFrameLoader (bug 672539)
+  // - HTMLBodyElement:       mContentStyleRule
+  // - HTMLDataListElement:   mOptions
+  // - HTMLFieldSetElement:   mElements, mDependentElements, mFirstLegend
+  // - HTMLFormElement:       many!
+  // - HTMLFrameSetElement:   mRowSpecs, mColSpecs
+  // - HTMLInputElement:      mInputData, mFiles, mFileList, mStaticDocfileList
+  // - nsHTMLMapElement:      mAreas
+  // - HTMLMediaElement:      many!
+  // - nsHTMLOutputElement:   mDefaultValue, mTokenList
+  // - nsHTMLRowElement:      mCells
+  // - nsHTMLSelectElement:   mOptions, mRestoreState
+  // - nsHTMLTableElement:    mTBodies, mRows, mTableInheritedAttributes
+  // - nsHTMLTableSectionElement: mRows
+  // - nsHTMLTextAreaElement: mControllers, mState
+  //
+  // The following members don't need to be measured:
+  // - nsIContent: mPrimaryFrame, because it's non-owning and measured elsewhere
+  //
+  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+  // SizeOfIncludingThis doesn't need to be overridden by sub-classes because
+  // sub-classes of nsINode are guaranteed to be laid out in memory in such a
+  // way that |this| points to the start of the allocated object, even in
+  // methods of nsINode's sub-classes, and so |aMallocSizeOf(this)| is always
+  // safe to call no matter which object it was invoked on.
+  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+  friend class nsNodeUtils;
+  friend class nsNodeWeakReference;
+  friend class nsNodeSupportsWeakRefTearoff;
+  friend class nsAttrAndChildArray;
+
+#ifdef MOZILLA_INTERNAL_API
+  explicit nsINode(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  : mNodeInfo(aNodeInfo)
+  , mParent(nullptr)
+  , mBoolFlags(0)
+  , mNextSibling(nullptr)
+  , mPreviousSibling(nullptr)
+  , mFirstChild(nullptr)
+  , mSubtreeRoot(this)
+  , mSlots(nullptr)
+  {
+  }
+#endif
+
+  virtual ~nsINode();
+
+  /**
+   * Bit-flags to pass (or'ed together) to IsNodeOfType()
+   */
+  enum {
+    /** nsIContent nodes */
+    eCONTENT             = 1 << 0,
+    /** nsIDocument nodes */
+    eDOCUMENT            = 1 << 1,
+    /** nsIAttribute nodes */
+    eATTRIBUTE           = 1 << 2,
+    /** text nodes */
+    eTEXT                = 1 << 3,
+    /** xml processing instructions */
+    ePROCESSING_INSTRUCTION = 1 << 4,
+    /** comment nodes */
+    eCOMMENT             = 1 << 5,
+    /** form control elements */
+    eHTML_FORM_CONTROL   = 1 << 6,
+    /** document fragments */
+    eDOCUMENT_FRAGMENT   = 1 << 7,
+    /** data nodes (comments, PIs, text). Nodes of this type always
+     returns a non-null value for nsIContent::GetText() */
+    eDATA_NODE           = 1 << 8,
+    /** HTMLMediaElement */
+    eMEDIA               = 1 << 9,
+    /** animation elements */
+    eANIMATION           = 1 << 10,
+    /** filter elements that implement SVGFilterPrimitiveStandardAttributes */
+    eFILTER              = 1 << 11
+  };
+
+  /**
+   * API for doing a quick check if a content is of a given
+   * type, such as Text, Document, Comment ...  Use this when you can instead of
+   * checking the tag.
+   *
+   * @param aFlags what types you want to test for (see above)
+   * @return whether the content matches ALL flags passed in
+   */
+  virtual bool IsNodeOfType(uint32_t aFlags) const = 0;
+
+  virtual JSObject* WrapObject(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
+
+  /**
+   * returns true if we are in priviliged code or
+   * layout.css.getBoxQuads.enabled == true.
+   */
+  static bool HasBoxQuadsSupport(JSContext* aCx, JSObject* /* unused */);
+
+protected:
+  /**
+   * WrapNode is called from WrapObject to actually wrap this node, WrapObject
+   * does some additional checks and fix-up that's common to all nodes. WrapNode
+   * should just call the DOM binding's Wrap function.
+   *
+   * aGivenProto is the prototype to use (or null if the default one should be
+   * used) and should just be passed directly on to the DOM binding's Wrap
+   * function.
+   */
+  virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) = 0;
+
+public:
+  mozilla::dom::ParentObject GetParentObject() const; // Implemented in nsIDocument.h
+
+  /**
+   * Return the scope chain parent for this node, for use in things
+   * like event handler compilation.  Returning null means to use the
+   * global object as the scope chain parent.
+   */
+  virtual nsINode* GetScopeChainParent() const;
+
+  /**
+   * Return whether the node is an Element node
+   */
+  bool IsElement() const {
+    return GetBoolFlag(NodeIsElement);
+  }
+
+  /**
+   * Return this node as an Element.  Should only be used for nodes
+   * for which IsElement() is true.  This is defined inline in Element.h.
+   */
+  mozilla::dom::Element* AsElement();
+  const mozilla::dom::Element* AsElement() const;
+
+  /**
+   * Return this node as nsIContent.  Should only be used for nodes for which
+   * IsContent() is true.  This is defined inline in nsIContent.h.
+   */
+  nsIContent* AsContent();
+  const nsIContent* AsContent() const
+  {
+    return const_cast<nsINode*>(this)->AsContent();
+  }
+
+  /**
+   * Return this node as Text if it is one, otherwise null.  This is defined
+   * inline in Text.h.
+   */
+  mozilla::dom::Text* GetAsText();
+  const mozilla::dom::Text* GetAsText() const;
+
+  virtual nsIDOMNode* AsDOMNode() = 0;
+
+  /**
+   * Return if this node has any children.
+   */
+  bool HasChildren() const { return !!mFirstChild; }
+
+  /**
+   * Get the number of children
+   * @return the number of children
+   */
+  virtual uint32_t GetChildCount() const = 0;
+
+  /**
+   * Get a child by index
+   * @param aIndex the index of the child to get
+   * @return the child, or null if index out of bounds
+   */
+  virtual nsIContent* GetChildAt(uint32_t aIndex) const = 0;
+
+  /**
+   * Get a raw pointer to the child array.  This should only be used if you
+   * plan to walk a bunch of the kids, promise to make sure that nothing ever
+   * mutates (no attribute changes, not DOM tree changes, no script execution,
+   * NOTHING), and will never ever peform an out-of-bounds access here.  This
+   * method may return null if there are no children, or it may return a
+   * garbage pointer.  In all cases the out param will be set to the number of
+   * children.
+   */
+  virtual nsIContent * const * GetChildArray(uint32_t* aChildCount) const = 0;
+
+  /**
+   * Get the index of a child within this content
+   * @param aPossibleChild the child to get the index of.
+   * @return the index of the child, or -1 if not a child
+   *
+   * If the return value is not -1, then calling GetChildAt() with that value
+   * will return aPossibleChild.
+   */
+  virtual int32_t IndexOf(const nsINode* aPossibleChild) const = 0;
+
+  /**
+   * Returns the "node document" of this node.
+   *
+   * https://dom.spec.whatwg.org/#concept-node-document
+   *
+   * Note that in the case that this node is a document node this method
+   * will return |this|.  That is different to the Node.ownerDocument DOM
+   * attribute (implemented by nsINode::GetOwnerDocument) which is specified to
+   * be null in that case:
+   *
+   * https://dom.spec.whatwg.org/#dom-node-ownerdocument
+   *
+   * For all other cases OwnerDoc and GetOwnerDocument behave identically.
+   */
+  nsIDocument *OwnerDoc() const
+  {
+    return mNodeInfo->GetDocument();
+  }
+
+  /**
+   * Return the "owner document" of this node as an nsINode*.  Implemented
+   * in nsIDocument.h.
+   */
+  nsINode *OwnerDocAsNode() const;
+
+  /**
+   * Returns true if the content has an ancestor that is a document.
+   *
+   * @return whether this content is in a document tree
+   */
+  bool IsInUncomposedDoc() const
+  {
+    return GetBoolFlag(IsInDocument);
+  }
+
+  /**
+   * Get the document that this content is currently in, if any. This will be
+   * null if the content has no ancestor that is a document.
+   *
+   * @return the current document
+   */
+
+  nsIDocument* GetUncomposedDoc() const
+  {
+    return IsInUncomposedDoc() ? OwnerDoc() : nullptr;
+  }
+
+  /**
+   * This method returns the owner doc if the node is in the
+   * composed document (as defined in the Shadow DOM spec), otherwise
+   * it returns null.
+   */
+  nsIDocument* GetComposedDoc() const
+  {
+    return IsInShadowTree() ?
+      GetComposedDocInternal() : GetUncomposedDoc();
+  }
+
+  /**
+   * Returns true if GetComposedDoc() would return a non-null value.
+   */
+  bool IsInComposedDoc() const
+  {
+    return IsInUncomposedDoc() || (IsInShadowTree() && GetComposedDocInternal());
+  }
+
+  /**
+   * The values returned by this function are the ones defined for
+   * nsIDOMNode.nodeType
+   */
+  uint16_t NodeType() const
+  {
+    return mNodeInfo->NodeType();
+  }
+  const nsString& NodeName() const
+  {
+    return mNodeInfo->NodeName();
+  }
+  const nsString& LocalName() const
+  {
+    return mNodeInfo->LocalName();
+  }
+
+  /**
+   * Get the NodeInfo for this element
+   * @return the nodes node info
+   */
+  inline mozilla::dom::NodeInfo* NodeInfo() const
+  {
+    return mNodeInfo;
+  }
+
+  inline bool IsInNamespace(int32_t aNamespace) const
+  {
+    return mNodeInfo->NamespaceID() == aNamespace;
+  }
+
+  /**
+   * Print a debugger friendly descriptor of this element. This will describe
+   * the position of this element in the document.
+   */
+  friend std::ostream& operator<<(std::ostream& aStream, const nsINode& aNode);
+
+protected:
+  // These 2 methods are useful for the recursive templates IsHTMLElement,
+  // IsSVGElement, etc.
+  inline bool IsNodeInternal() const
+  {
+    return false;
+  }
+
+  template<typename First, typename... Args>
+  inline bool IsNodeInternal(First aFirst, Args... aArgs) const
+  {
+    return mNodeInfo->Equals(aFirst) || IsNodeInternal(aArgs...);
+  }
+
+public:
+  inline bool IsHTMLElement() const
+  {
+    return IsElement() && IsInNamespace(kNameSpaceID_XHTML);
+  }
+
+  inline bool IsHTMLElement(nsIAtom* aTag) const
+  {
+    return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_XHTML);
+  }
+
+  template<typename First, typename... Args>
+  inline bool IsAnyOfHTMLElements(First aFirst, Args... aArgs) const
+  {
+    return IsHTMLElement() && IsNodeInternal(aFirst, aArgs...);
+  }
+
+  inline bool IsSVGElement() const
+  {
+    return IsElement() && IsInNamespace(kNameSpaceID_SVG);
+  }
+
+  inline bool IsSVGElement(nsIAtom* aTag) const
+  {
+    return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_SVG);
+  }
+
+  template<typename First, typename... Args>
+  inline bool IsAnyOfSVGElements(First aFirst, Args... aArgs) const
+  {
+    return IsSVGElement() && IsNodeInternal(aFirst, aArgs...);
+  }
+
+  inline bool IsXULElement() const
+  {
+    return IsElement() && IsInNamespace(kNameSpaceID_XUL);
+  }
+
+  inline bool IsXULElement(nsIAtom* aTag) const
+  {
+    return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_XUL);
+  }
+
+  template<typename First, typename... Args>
+  inline bool IsAnyOfXULElements(First aFirst, Args... aArgs) const
+  {
+    return IsXULElement() && IsNodeInternal(aFirst, aArgs...);
+  }
+
+  inline bool IsMathMLElement() const
+  {
+    return IsElement() && IsInNamespace(kNameSpaceID_MathML);
+  }
+
+  inline bool IsMathMLElement(nsIAtom* aTag) const
+  {
+    return IsElement() && mNodeInfo->Equals(aTag, kNameSpaceID_MathML);
+  }
+
+  template<typename First, typename... Args>
+  inline bool IsAnyOfMathMLElements(First aFirst, Args... aArgs) const
+  {
+    return IsMathMLElement() && IsNodeInternal(aFirst, aArgs...);
+  }
+
+  /**
+   * Insert a content node at a particular index.  This method handles calling
+   * BindToTree on the child appropriately.
+   *
+   * @param aKid the content to insert
+   * @param aIndex the index it is being inserted at (the index it will have
+   *        after it is inserted)
+   * @param aNotify whether to notify the document (current document for
+   *        nsIContent, and |this| for nsIDocument) that the insert has
+   *        occurred
+   *
+   * @throws NS_ERROR_DOM_HIERARCHY_REQUEST_ERR if one attempts to have more
+   * than one element node as a child of a document.  Doing this will also
+   * assert -- you shouldn't be doing it!  Check with
+   * nsIDocument::GetRootElement() first if you're not sure.  Apart from this
+   * one constraint, this doesn't do any checking on whether aKid is a valid
+   * child of |this|.
+   *
+   * @throws NS_ERROR_OUT_OF_MEMORY in some cases (from BindToTree).
+   */
+  virtual nsresult InsertChildAt(nsIContent* aKid, uint32_t aIndex,
+                                 bool aNotify) = 0;
+
+  /**
+   * Append a content node to the end of the child list.  This method handles
+   * calling BindToTree on the child appropriately.
+   *
+   * @param aKid the content to append
+   * @param aNotify whether to notify the document (current document for
+   *        nsIContent, and |this| for nsIDocument) that the append has
+   *        occurred
+   *
+   * @throws NS_ERROR_DOM_HIERARCHY_REQUEST_ERR if one attempts to have more
+   * than one element node as a child of a document.  Doing this will also
+   * assert -- you shouldn't be doing it!  Check with
+   * nsIDocument::GetRootElement() first if you're not sure.  Apart from this
+   * one constraint, this doesn't do any checking on whether aKid is a valid
+   * child of |this|.
+   *
+   * @throws NS_ERROR_OUT_OF_MEMORY in some cases (from BindToTree).
+   */
+  nsresult AppendChildTo(nsIContent* aKid, bool aNotify)
+  {
+    return InsertChildAt(aKid, GetChildCount(), aNotify);
+  }
+
+  /**
+   * Remove a child from this node.  This method handles calling UnbindFromTree
+   * on the child appropriately.
+   *
+   * @param aIndex the index of the child to remove
+   * @param aNotify whether to notify the document (current document for
+   *        nsIContent, and |this| for nsIDocument) that the remove has
+   *        occurred
+   *
+   * Note: If there is no child at aIndex, this method will simply do nothing.
+   */
+  virtual void RemoveChildAt(uint32_t aIndex, bool aNotify) = 0;
+
+  /**
+   * Get a property associated with this node.
+   *
+   * @param aPropertyName  name of property to get.
+   * @param aStatus        out parameter for storing resulting status.
+   *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
+   *                       is not set.
+   * @return               the property. Null if the property is not set
+   *                       (though a null return value does not imply the
+   *                       property was not set, i.e. it can be set to null).
+   */
+  void* GetProperty(nsIAtom *aPropertyName,
+                    nsresult *aStatus = nullptr) const
+  {
+    return GetProperty(0, aPropertyName, aStatus);
+  }
+
+  /**
+   * Get a property associated with this node.
+   *
+   * @param aCategory      category of property to get.
+   * @param aPropertyName  name of property to get.
+   * @param aStatus        out parameter for storing resulting status.
+   *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
+   *                       is not set.
+   * @return               the property. Null if the property is not set
+   *                       (though a null return value does not imply the
+   *                       property was not set, i.e. it can be set to null).
+   */
+  void* GetProperty(uint16_t aCategory, nsIAtom *aPropertyName,
+                    nsresult *aStatus = nullptr) const;
+
+  /**
+   * Set a property to be associated with this node. This will overwrite an
+   * existing value if one exists. The existing value is destroyed using the
+   * destructor function given when that value was set.
+   *
+   * @param aPropertyName  name of property to set.
+   * @param aValue         new value of property.
+   * @param aDtor          destructor function to be used when this property
+   *                       is destroyed.
+   * @param aTransfer      if true the property will not be deleted when the
+   *                       ownerDocument of the node changes, if false it
+   *                       will be deleted.
+   *
+   * @return NS_PROPTABLE_PROP_OVERWRITTEN (success value) if the property
+   *                                       was already set
+   * @throws NS_ERROR_OUT_OF_MEMORY if that occurs
+   */
+  nsresult SetProperty(nsIAtom *aPropertyName, void *aValue,
+                       NSPropertyDtorFunc aDtor = nullptr,
+                       bool aTransfer = false)
+  {
+    return SetProperty(0, aPropertyName, aValue, aDtor, aTransfer);
+  }
+
+  /**
+   * Set a property to be associated with this node. This will overwrite an
+   * existing value if one exists. The existing value is destroyed using the
+   * destructor function given when that value was set.
+   *
+   * @param aCategory       category of property to set.
+   * @param aPropertyName   name of property to set.
+   * @param aValue          new value of property.
+   * @param aDtor           destructor function to be used when this property
+   *                        is destroyed.
+   * @param aTransfer       if true the property will not be deleted when the
+   *                        ownerDocument of the node changes, if false it
+   *                        will be deleted.
+   * @param aOldValue [out] previous value of property.
+   *
+   * @return NS_PROPTABLE_PROP_OVERWRITTEN (success value) if the property
+   *                                       was already set
+   * @throws NS_ERROR_OUT_OF_MEMORY if that occurs
+   */
+  nsresult SetProperty(uint16_t aCategory,
+                       nsIAtom *aPropertyName, void *aValue,
+                       NSPropertyDtorFunc aDtor = nullptr,
+                       bool aTransfer = false,
+                       void **aOldValue = nullptr);
+
+  /**
+   * A generic destructor for property values allocated with new.
+   */
+  template<class T>
+  static void DeleteProperty(void *, nsIAtom *, void *aPropertyValue, void *)
+  {
+    delete static_cast<T *>(aPropertyValue);
+  }
+
+  /**
+   * Destroys a property associated with this node. The value is destroyed
+   * using the destruction function given when that value was set.
+   *
+   * @param aPropertyName  name of property to destroy.
+   */
+  void DeleteProperty(nsIAtom *aPropertyName)
+  {
+    DeleteProperty(0, aPropertyName);
+  }
+
+  /**
+   * Destroys a property associated with this node. The value is destroyed
+   * using the destruction function given when that value was set.
+   *
+   * @param aCategory      category of property to destroy.
+   * @param aPropertyName  name of property to destroy.
+   */
+  void DeleteProperty(uint16_t aCategory, nsIAtom *aPropertyName);
+
+  /**
+   * Unset a property associated with this node. The value will not be
+   * destroyed but rather returned. It is the caller's responsibility to
+   * destroy the value after that point.
+   *
+   * @param aPropertyName  name of property to unset.
+   * @param aStatus        out parameter for storing resulting status.
+   *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
+   *                       is not set.
+   * @return               the property. Null if the property is not set
+   *                       (though a null return value does not imply the
+   *                       property was not set, i.e. it can be set to null).
+   */
+  void* UnsetProperty(nsIAtom  *aPropertyName,
+                      nsresult *aStatus = nullptr)
+  {
+    return UnsetProperty(0, aPropertyName, aStatus);
+  }
+
+  /**
+   * Unset a property associated with this node. The value will not be
+   * destroyed but rather returned. It is the caller's responsibility to
+   * destroy the value after that point.
+   *
+   * @param aCategory      category of property to unset.
+   * @param aPropertyName  name of property to unset.
+   * @param aStatus        out parameter for storing resulting status.
+   *                       Set to NS_PROPTABLE_PROP_NOT_THERE if the property
+   *                       is not set.
+   * @return               the property. Null if the property is not set
+   *                       (though a null return value does not imply the
+   *                       property was not set, i.e. it can be set to null).
+   */
+  void* UnsetProperty(uint16_t aCategory, nsIAtom *aPropertyName,
+                      nsresult *aStatus = nullptr);
+
+  bool HasProperties() const
+  {
+    return HasFlag(NODE_HAS_PROPERTIES);
+  }
+
+  /**
+   * Return the principal of this node.  This is guaranteed to never be a null
+   * pointer.
+   */
+  nsIPrincipal* NodePrincipal() const {
+    return mNodeInfo->NodeInfoManager()->DocumentPrincipal();
+  }
+
+  /**
+   * Get the parent nsIContent for this node.
+   * @return the parent, or null if no parent or the parent is not an nsIContent
+   */
+  nsIContent* GetParent() const {
+    return MOZ_LIKELY(GetBoolFlag(ParentIsContent)) ?
+      reinterpret_cast<nsIContent*>(mParent) : nullptr;
+  }
+
+  /**
+   * Get the parent nsINode for this node. This can be either an nsIContent,
+   * an nsIDocument or an nsIAttribute.
+   * @return the parent node
+   */
+  nsINode* GetParentNode() const
+  {
+    return mParent;
+  }
+
+  /**
+   * Returns the node that is the parent of this node in the flattened
+   * tree. This differs from the normal parent if the node is filtered
+   * into an insertion point, or if the node is a direct child of a
+   * shadow root.
+   *
+   * @return the flattened tree parent
+   */
+  inline nsINode* GetFlattenedTreeParentNode() const;
+
+  /**
+   * Get the parent nsINode for this node if it is an Element.
+   * @return the parent node
+   */
+  mozilla::dom::Element* GetParentElement() const
+  {
+    return mParent && mParent->IsElement() ? mParent->AsElement() : nullptr;
+  }
+
+  /**
+   * Get the parent Element of this node, traversing over a ShadowRoot
+   * to its host if necessary.
+   */
+  mozilla::dom::Element* GetParentElementCrossingShadowRoot() const;
+
+  /**
+   * Get the root of the subtree this node belongs to.  This never returns
+   * null.  It may return 'this' (e.g. for document nodes, and nodes that
+   * are the roots of disconnected subtrees).
+   */
+  nsINode* SubtreeRoot() const;
+
+  nsINode* RootNode() const
+  {
+    return SubtreeRoot();
+  }
+
+  /**
+   * See nsIDOMEventTarget
+   */
+  NS_DECL_NSIDOMEVENTTARGET
+
+  virtual mozilla::EventListenerManager*
+    GetExistingListenerManager() const override;
+  virtual mozilla::EventListenerManager*
+    GetOrCreateListenerManager() override;
+
+  using mozilla::dom::EventTarget::RemoveEventListener;
+  using nsIDOMEventTarget::AddEventListener;
+  virtual void AddEventListener(const nsAString& aType,
+                                mozilla::dom::EventListener* aListener,
+                                const mozilla::dom::AddEventListenerOptionsOrBoolean& aOptions,
+                                const mozilla::dom::Nullable<bool>& aWantsUntrusted,
+                                mozilla::ErrorResult& aRv) override;
+  using nsIDOMEventTarget::AddSystemEventListener;
+
+  virtual bool IsApzAware() const override;
+
+  virtual nsPIDOMWindowOuter* GetOwnerGlobalForBindings() override;
+  virtual nsIGlobalObject* GetOwnerGlobal() const override;
+
+  /**
+   * Returns true if this is a node belonging to a document that uses the Servo
+   * style system.
+   */
+#ifdef MOZ_STYLO
+  bool IsStyledByServo() const;
+#else
+  bool IsStyledByServo() const { return false; }
+#endif
+
+  bool IsDirtyForServo() const
+  {
+    MOZ_ASSERT(IsStyledByServo());
+    return HasFlag(NODE_IS_DIRTY_FOR_SERVO);
+  }
+
+  bool HasDirtyDescendantsForServo() const
+  {
+    MOZ_ASSERT(IsStyledByServo());
+    return HasFlag(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
+  }
+
+  void SetIsDirtyForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    SetFlags(NODE_IS_DIRTY_FOR_SERVO);
+  }
+
+  void SetHasDirtyDescendantsForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    SetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
+  }
+
+  void SetIsDirtyAndHasDirtyDescendantsForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    SetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO | NODE_IS_DIRTY_FOR_SERVO);
+  }
+
+  void UnsetIsDirtyForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    UnsetFlags(NODE_IS_DIRTY_FOR_SERVO);
+  }
+
+  void UnsetHasDirtyDescendantsForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    UnsetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO);
+  }
+
+  void UnsetIsDirtyAndHasDirtyDescendantsForServo() {
+    MOZ_ASSERT(IsStyledByServo());
+    UnsetFlags(NODE_HAS_DIRTY_DESCENDANTS_FOR_SERVO | NODE_IS_DIRTY_FOR_SERVO);
+  }
+
+  inline void UnsetRestyleFlagsIfGecko();
+
+  /**
+   * Adds a mutation observer to be notified when this node, or any of its
+   * descendants, are modified. The node will hold a weak reference to the
+   * observer, which means that it is the responsibility of the observer to
+   * remove itself in case it dies before the node.  If an observer is added
+   * while observers are being notified, it may also be notified.  In general,
+   * adding observers while inside a notification is not a good idea.  An
+   * observer that is already observing the node must not be added without
+   * being removed first.
+   *
+   * For mutation observers that implement nsIAnimationObserver, use
+   * AddAnimationObserver instead.
+   */
+  void AddMutationObserver(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* s = Slots();
+    NS_ASSERTION(s->mMutationObservers.IndexOf(aMutationObserver) ==
+                 nsTArray<int>::NoIndex,
+                 "Observer already in the list");
+    s->mMutationObservers.AppendElement(aMutationObserver);
+  }
+
+  /**
+   * Same as above, but only adds the observer if its not observing
+   * the node already.
+   *
+   * For mutation observers that implement nsIAnimationObserver, use
+   * AddAnimationObserverUnlessExists instead.
+   */
+  void AddMutationObserverUnlessExists(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* s = Slots();
+    s->mMutationObservers.AppendElementUnlessExists(aMutationObserver);
+  }
+
+  /**
+   * Same as AddMutationObserver, but for nsIAnimationObservers.  This
+   * additionally records on the document that animation observers have
+   * been registered, which is used to determine whether notifications
+   * must be fired when animations are added, removed or changed.
+   */
+  void AddAnimationObserver(nsIAnimationObserver* aAnimationObserver);
+
+  /**
+   * Same as above, but only adds the observer if its not observing
+   * the node already.
+   */
+  void AddAnimationObserverUnlessExists(nsIAnimationObserver* aAnimationObserver);
+
+  /**
+   * Removes a mutation observer.
+   */
+  void RemoveMutationObserver(nsIMutationObserver* aMutationObserver)
+  {
+    nsSlots* s = GetExistingSlots();
+    if (s) {
+      s->mMutationObservers.RemoveElement(aMutationObserver);
+    }
+  }
+
+  /**
+   * Clones this node. This needs to be overriden by all node classes. aNodeInfo
+   * should be identical to this node's nodeInfo, except for the document which
+   * may be different. When cloning an element, all attributes of the element
+   * will be cloned. The children of the node will not be cloned.
+   *
+   * @param aNodeInfo the nodeinfo to use for the clone
+   * @param aResult the clone
+   */
+  virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const = 0;
+
+  // This class can be extended by subclasses that wish to store more
+  // information in the slots.
+  class nsSlots
+  {
+  public:
+    nsSlots();
+
+    // If needed we could remove the vtable pointer this dtor causes by
+    // putting a DestroySlots function on nsINode
+    virtual ~nsSlots();
+
+    void Traverse(nsCycleCollectionTraversalCallback &cb);
+    void Unlink();
+
+    /**
+     * A list of mutation observers
+     */
+    nsTObserverArray<nsIMutationObserver*> mMutationObservers;
+
+    /**
+     * An object implementing nsIDOMNodeList for this content (childNodes)
+     * @see nsIDOMNodeList
+     * @see nsGenericHTMLElement::GetChildNodes
+     */
+    RefPtr<nsChildContentList> mChildNodes;
+
+    /**
+     * Weak reference to this node.  This is cleared by the destructor of
+     * nsNodeWeakReference.
+     */
+    nsNodeWeakReference* MOZ_NON_OWNING_REF mWeakReference;
+
+    /**
+     * Number of descendant nodes in the uncomposed document that have been
+     * explicitly set as editable.
+     */
+    uint32_t mEditableDescendantCount;
+  };
+
+  /**
+   * Functions for managing flags and slots
+   */
+#ifdef DEBUG
+  nsSlots* DebugGetSlots()
+  {
+    return Slots();
+  }
+#endif
+
+  void SetFlags(FlagsType aFlagsToSet)
+  {
+    NS_ASSERTION(!(aFlagsToSet & (NODE_IS_ANONYMOUS_ROOT |
+                                  NODE_IS_NATIVE_ANONYMOUS_ROOT |
+                                  NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE |
+                                  NODE_DESCENDANTS_NEED_FRAMES |
+                                  NODE_NEEDS_FRAME |
+                                  NODE_CHROME_ONLY_ACCESS)) ||
+                 IsNodeOfType(eCONTENT),
+                 "Flag only permitted on nsIContent nodes");
+    nsWrapperCache::SetFlags(aFlagsToSet);
+  }
+
+  void UnsetFlags(FlagsType aFlagsToUnset)
+  {
+    NS_ASSERTION(!(aFlagsToUnset &
+                   (NODE_IS_ANONYMOUS_ROOT |
+                    NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE |
+                    NODE_IS_NATIVE_ANONYMOUS_ROOT)),
+                 "Trying to unset write-only flags");
+    nsWrapperCache::UnsetFlags(aFlagsToUnset);
+  }
+
+  void ChangeEditableDescendantCount(int32_t aDelta);
+
+  /**
+   * Returns the count of descendant nodes in the uncomposed
+   * document that are explicitly set as editable.
+   */
+  uint32_t EditableDescendantCount();
+
+  /**
+   * Sets the editable descendant count to 0. The editable
+   * descendant count only counts explicitly editable nodes
+   * that are in the uncomposed document so this method
+   * should be called when nodes are are removed from it.
+   */
+  void ResetEditableDescendantCount();
+
+  void SetEditableFlag(bool aEditable)
+  {
+    if (aEditable) {
+      SetFlags(NODE_IS_EDITABLE);
+    }
+    else {
+      UnsetFlags(NODE_IS_EDITABLE);
+    }
+  }
+
+  bool IsEditable() const
+  {
+#ifdef MOZILLA_INTERNAL_API
+    return IsEditableInternal();
+#else
+    return IsEditableExternal();
+#endif
+  }
+
+  /**
+   * Returns true if |this| or any of its ancestors is native anonymous.
+   */
+  bool IsInNativeAnonymousSubtree() const
+  {
+#ifdef DEBUG
+    if (HasFlag(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE)) {
+      return true;
+    }
+    CheckNotNativeAnonymous();
+    return false;
+#else
+    return HasFlag(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE);
+#endif
+  }
+
+  bool IsInAnonymousSubtree() const;
+
+  // Note: This asserts |IsInAnonymousSubtree()|.
+  bool IsAnonymousContentInSVGUseSubtree() const;
+
+  // True for native anonymous content and for XBL content if the binding
+  // has chromeOnlyContent="true".
+  bool ChromeOnlyAccess() const
+  {
+    return HasFlag(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE | NODE_CHROME_ONLY_ACCESS);
+  }
+
+  bool IsInShadowTree() const
+  {
+    return HasFlag(NODE_IS_IN_SHADOW_TREE);
+  }
+
+  /**
+   * Returns true if |this| node is the common ancestor of the start/end
+   * nodes of a Range in a Selection or a descendant of such a common ancestor.
+   * This node is definitely not selected when |false| is returned, but it may
+   * or may not be selected when |true| is returned.
+   */
+  bool IsSelectionDescendant() const
+  {
+    return IsDescendantOfCommonAncestorForRangeInSelection() ||
+           IsCommonAncestorForRangeInSelection();
+  }
+
+  /**
+   * Get the root content of an editor. So, this node must be a descendant of
+   * an editor. Note that this should be only used for getting input or textarea
+   * editor's root content. This method doesn't support HTML editors.
+   */
+  nsIContent* GetTextEditorRootContent(nsIEditor** aEditor = nullptr);
+
+  /**
+   * Get the nearest selection root, ie. the node that will be selected if the
+   * user does "Select All" while the focus is in this node. Note that if this
+   * node is not in an editor, the result comes from the nsFrameSelection that
+   * is related to aPresShell, so the result might not be the ancestor of this
+   * node. Be aware that if this node and the computed selection limiter are
+   * not in same subtree, this returns the root content of the closeset subtree.
+   */
+  nsIContent* GetSelectionRootContent(nsIPresShell* aPresShell);
+
+  virtual nsINodeList* ChildNodes();
+  nsIContent* GetFirstChild() const { return mFirstChild; }
+  nsIContent* GetLastChild() const
+  {
+    uint32_t count;
+    nsIContent* const* children = GetChildArray(&count);
+
+    return count > 0 ? children[count - 1] : nullptr;
+  }
+
+  /**
+   * Implementation is in nsIDocument.h, because it needs to cast from
+   * nsIDocument* to nsINode*.
+   */
+  nsIDocument* GetOwnerDocument() const;
+
+  void Normalize();
+
+  /**
+   * Get the base URI for any relative URIs within this piece of
+   * content. Generally, this is the document's base URI, but certain
+   * content carries a local base for backward compatibility, and XML
+   * supports setting a per-node base URI.
+   *
+   * @return the base URI
+   */
+  virtual already_AddRefed<nsIURI> GetBaseURI(bool aTryUseXHRDocBaseURI = false) const = 0;
+  already_AddRefed<nsIURI> GetBaseURIObject() const;
+
+  /**
+   * Facility for explicitly setting a base URI on a node.
+   */
+  nsresult SetExplicitBaseURI(nsIURI* aURI);
+  /**
+   * The explicit base URI, if set, otherwise null
+   */
+
+  /**
+   * Return true if the node may be apz aware. There are two cases. One is that
+   * the node is apz aware (such as HTMLInputElement with number type). The
+   * other is that the node has apz aware listeners. This is a non-virtual
+   * function which calls IsNodeApzAwareInternal only when the MayBeApzAware is
+   * set. We check the details in IsNodeApzAwareInternal which may be overriden
+   * by child classes
+   */
+  bool IsNodeApzAware() const
+  {
+    return NodeMayBeApzAware() ? IsNodeApzAwareInternal() : false;
+  }
+
+  /**
+   * Override this function and set the flag MayBeApzAware in case the node has
+   * to let APZC be aware of it. It's used when the node may handle the apz
+   * aware events and may do preventDefault to stop APZC to do default actions.
+   *
+   * For example, instead of scrolling page by APZ, we handle mouse wheel event
+   * in HTMLInputElement with number type as increasing / decreasing its value.
+   */
+  virtual bool IsNodeApzAwareInternal() const;
+
+  // HTML elements named <shadow> may or may not be HTMLShadowElement.  This is
+  // a way to ask an element whether it's an HTMLShadowElement.
+  virtual bool IsHTMLShadowElement() const { return false; }
+
+  // Elements named <content> may or may not be HTMLContentElement.  This is a
+  // way to ask an element whether it's an HTMLContentElement.
+  virtual bool IsHTMLContentElement() const { return false; }
+
+protected:
+  nsIURI* GetExplicitBaseURI() const {
+    if (HasExplicitBaseURI()) {
+      return static_cast<nsIURI*>(GetProperty(nsGkAtoms::baseURIProperty));
+    }
+    return nullptr;
+  }
+
+public:
+  void GetTextContent(nsAString& aTextContent,
+                      mozilla::ErrorResult& aError)
+  {
+    GetTextContentInternal(aTextContent, aError);
+  }
+  void SetTextContent(const nsAString& aTextContent,
+                      mozilla::ErrorResult& aError)
+  {
+    SetTextContentInternal(aTextContent, aError);
+  }
+
+  mozilla::dom::Element* QuerySelector(const nsAString& aSelector,
+                                       mozilla::ErrorResult& aResult);
+  already_AddRefed<nsINodeList> QuerySelectorAll(const nsAString& aSelector,
+                                                 mozilla::ErrorResult& aResult);
+
+  nsresult QuerySelector(const nsAString& aSelector, nsIDOMElement **aReturn);
+  nsresult QuerySelectorAll(const nsAString& aSelector, nsIDOMNodeList **aReturn);
+
+protected:
+  // nsIDocument overrides this with its own (faster) version.  This
+  // should really only be called for elements and document fragments.
+  mozilla::dom::Element* GetElementById(const nsAString& aId);
+
+public:
+  /**
+   * Associate an object aData to aKey on this node. If aData is null any
+   * previously registered object associated to aKey on this node will
+   * be removed.
+   * Should only be used to implement the DOM Level 3 UserData API.
+   *
+   * @param aKey the key to associate the object to
+   * @param aData the object to associate to aKey on this node (may be null)
+   * @param aResult [out] the previously registered object for aKey on this
+   *                      node, if any
+   * @return whether adding the object succeeded
+   */
+  nsresult SetUserData(const nsAString& aKey, nsIVariant* aData,
+                       nsIVariant** aResult);
+
+  /**
+   * Get the UserData object registered for a Key on this node, if any.
+   * Should only be used to implement the DOM Level 3 UserData API.
+   *
+   * @param aKey the key to get UserData for
+   * @return aResult the previously registered object for aKey on this node, if
+   *                 any
+   */
+  nsIVariant* GetUserData(const nsAString& aKey);
+
+  nsresult GetUserData(const nsAString& aKey, nsIVariant** aResult)
+  {
+    NS_IF_ADDREF(*aResult = GetUserData(aKey));
+
+    return NS_OK;
+  }
+
+  void LookupPrefix(const nsAString& aNamespace, nsAString& aResult);
+  bool IsDefaultNamespace(const nsAString& aNamespaceURI)
+  {
+    nsAutoString defaultNamespace;
+    LookupNamespaceURI(EmptyString(), defaultNamespace);
+    return aNamespaceURI.Equals(defaultNamespace);
+  }
+  void LookupNamespaceURI(const nsAString& aNamespacePrefix,
+                          nsAString& aNamespaceURI);
+
+  nsresult IsEqualNode(nsIDOMNode* aOther, bool* aReturn);
+
+  nsIContent* GetNextSibling() const { return mNextSibling; }
+  nsIContent* GetPreviousSibling() const { return mPreviousSibling; }
+
+  /**
+   * Get the next node in the pre-order tree traversal of the DOM.  If
+   * aRoot is non-null, then it must be an ancestor of |this|
+   * (possibly equal to |this|) and only nodes that are descendants of
+   * aRoot, not including aRoot itself, will be returned.  Returns
+   * null if there are no more nodes to traverse.
+   */
+  nsIContent* GetNextNode(const nsINode* aRoot = nullptr) const
+  {
+    return GetNextNodeImpl(aRoot, false);
+  }
+
+  /**
+   * Get the next node in the pre-order tree traversal of the DOM but ignoring
+   * the children of this node.  If aRoot is non-null, then it must be an
+   * ancestor of |this| (possibly equal to |this|) and only nodes that are
+   * descendants of aRoot, not including aRoot itself, will be returned.
+   * Returns null if there are no more nodes to traverse.
+   */
+  nsIContent* GetNextNonChildNode(const nsINode* aRoot = nullptr) const
+  {
+    return GetNextNodeImpl(aRoot, true);
+  }
+
+  /**
+   * Returns true if 'this' is either document or element or
+   * document fragment and aOther is a descendant in the same
+   * anonymous tree.
+   */
+  bool Contains(const nsINode* aOther) const;
+  nsresult Contains(nsIDOMNode* aOther, bool* aReturn);
+
+  bool UnoptimizableCCNode() const;
+
+private:
+
+  nsIDocument* GetComposedDocInternal() const;
+
+  nsIContent* GetNextNodeImpl(const nsINode* aRoot,
+                              const bool aSkipChildren) const
+  {
+    // Can't use nsContentUtils::ContentIsDescendantOf here, since we
+    // can't include it here.
+#ifdef DEBUG
+    if (aRoot) {
+      const nsINode* cur = this;
+      for (; cur; cur = cur->GetParentNode())
+        if (cur == aRoot) break;
+      NS_ASSERTION(cur, "aRoot not an ancestor of |this|?");
+    }
+#endif
+    if (!aSkipChildren) {
+      nsIContent* kid = GetFirstChild();
+      if (kid) {
+        return kid;
+      }
+    }
+    if (this == aRoot) {
+      return nullptr;
+    }
+    const nsINode* cur = this;
+    while (1) {
+      nsIContent* next = cur->GetNextSibling();
+      if (next) {
+        return next;
+      }
+      nsINode* parent = cur->GetParentNode();
+      if (parent == aRoot) {
+        return nullptr;
+      }
+      cur = parent;
+    }
+    NS_NOTREACHED("How did we get here?");
+  }
+
+public:
+
+  /**
+   * Get the previous nsIContent in the pre-order tree traversal of the DOM.  If
+   * aRoot is non-null, then it must be an ancestor of |this|
+   * (possibly equal to |this|) and only nsIContents that are descendants of
+   * aRoot, including aRoot itself, will be returned.  Returns
+   * null if there are no more nsIContents to traverse.
+   */
+  nsIContent* GetPreviousContent(const nsINode* aRoot = nullptr) const
+  {
+      // Can't use nsContentUtils::ContentIsDescendantOf here, since we
+      // can't include it here.
+#ifdef DEBUG
+      if (aRoot) {
+        const nsINode* cur = this;
+        for (; cur; cur = cur->GetParentNode())
+          if (cur == aRoot) break;
+        NS_ASSERTION(cur, "aRoot not an ancestor of |this|?");
+      }
+#endif
+
+    if (this == aRoot) {
+      return nullptr;
+    }
+    nsIContent* cur = this->GetParent();
+    nsIContent* iter = this->GetPreviousSibling();
+    while (iter) {
+      cur = iter;
+      iter = reinterpret_cast<nsINode*>(iter)->GetLastChild();
+    }
+    return cur;
+  }
+
+  /**
+   * Boolean flags
+   */
+private:
+  enum BooleanFlag {
+    // Set if we're being used from -moz-element
+    NodeHasRenderingObservers,
+    // Set if our parent chain (including this node itself) terminates
+    // in a document
+    IsInDocument,
+    // Set if mParent is an nsIContent
+    ParentIsContent,
+    // Set if this node is an Element
+    NodeIsElement,
+    // Set if the element has a non-empty id attribute. This can in rare
+    // cases lie for nsXMLElement, such as when the node has been moved between
+    // documents with different id mappings.
+    ElementHasID,
+    // Set if the element might have inline style.
+    ElementMayHaveStyle,
+    // Set if the element has a name attribute set.
+    ElementHasName,
+    // Set if the element might have a contenteditable attribute set.
+    ElementMayHaveContentEditableAttr,
+    // Set if the node is the common ancestor of the start/end nodes of a Range
+    // that is in a Selection.
+    NodeIsCommonAncestorForRangeInSelection,
+    // Set if the node is a descendant of a node with the above bit set.
+    NodeIsDescendantOfCommonAncestorForRangeInSelection,
+    // Set if CanSkipInCC check has been done for this subtree root.
+    NodeIsCCMarkedRoot,
+    // Maybe set if this node is in black subtree.
+    NodeIsCCBlackTree,
+    // Maybe set if the node is a root of a subtree
+    // which needs to be kept in the purple buffer.
+    NodeIsPurpleRoot,
+    // Set if the node has an explicit base URI stored
+    NodeHasExplicitBaseURI,
+    // Set if the element has some style states locked
+    ElementHasLockedStyleStates,
+    // Set if element has pointer locked
+    ElementHasPointerLock,
+    // Set if the node may have DOMMutationObserver attached to it.
+    NodeMayHaveDOMMutationObserver,
+    // Set if node is Content
+    NodeIsContent,
+    // Set if the node has animations or transitions
+    ElementHasAnimations,
+    // Set if node has a dir attribute with a valid value (ltr, rtl, or auto)
+    NodeHasValidDirAttribute,
+    // Set if node has a dir attribute with a fixed value (ltr or rtl, NOT auto)
+    NodeHasFixedDir,
+    // Set if the node has dir=auto and has a property pointing to the text
+    // node that determines its direction
+    NodeHasDirAutoSet,
+    // Set if the node is a text node descendant of a node with dir=auto
+    // and has a TextNodeDirectionalityMap property listing the elements whose
+    // direction it determines.
+    NodeHasTextNodeDirectionalityMap,
+    // Set if the node has dir=auto.
+    NodeHasDirAuto,
+    // Set if a node in the node's parent chain has dir=auto.
+    NodeAncestorHasDirAuto,
+    // Set if the element is in the scope of a scoped style sheet; this flag is
+    // only accurate for elements bound to a document
+    ElementIsInStyleScope,
+    // Set if the element is a scoped style sheet root
+    ElementIsScopedStyleRoot,
+    // Set if the node is handling a click.
+    NodeHandlingClick,
+    // Set if the node has had :hover selectors matched against it
+    NodeHasRelevantHoverRules,
+    // Set if the element has a parser insertion mode other than "in body",
+    // per the HTML5 "Parse state" section.
+    ElementHasWeirdParserInsertionMode,
+    // Parser sets this flag if it has notified about the node.
+    ParserHasNotified,
+    // Sets if the node is apz aware or we have apz aware listeners.
+    MayBeApzAware,
+    // Guard value
+    BooleanFlagCount
+  };
+
+  void SetBoolFlag(BooleanFlag name, bool value) {
+    static_assert(BooleanFlagCount <= 8*sizeof(mBoolFlags),
+                  "Too many boolean flags");
+    mBoolFlags = (mBoolFlags & ~(1 << name)) | (value << name);
+  }
+
+  void SetBoolFlag(BooleanFlag name) {
+    static_assert(BooleanFlagCount <= 8*sizeof(mBoolFlags),
+                  "Too many boolean flags");
+    mBoolFlags |= (1 << name);
+  }
+
+  void ClearBoolFlag(BooleanFlag name) {
+    static_assert(BooleanFlagCount <= 8*sizeof(mBoolFlags),
+                  "Too many boolean flags");
+    mBoolFlags &= ~(1 << name);
+  }
+
+  bool GetBoolFlag(BooleanFlag name) const {
+    static_assert(BooleanFlagCount <= 8*sizeof(mBoolFlags),
+                  "Too many boolean flags");
+    return mBoolFlags & (1 << name);
+  }
+
+public:
+  bool HasRenderingObservers() const
+    { return GetBoolFlag(NodeHasRenderingObservers); }
+  void SetHasRenderingObservers(bool aValue)
+    { SetBoolFlag(NodeHasRenderingObservers, aValue); }
+  bool IsContent() const { return GetBoolFlag(NodeIsContent); }
+  bool HasID() const { return GetBoolFlag(ElementHasID); }
+  bool MayHaveStyle() const { return GetBoolFlag(ElementMayHaveStyle); }
+  bool HasName() const { return GetBoolFlag(ElementHasName); }
+  bool MayHaveContentEditableAttr() const
+    { return GetBoolFlag(ElementMayHaveContentEditableAttr); }
+  bool IsCommonAncestorForRangeInSelection() const
+    { return GetBoolFlag(NodeIsCommonAncestorForRangeInSelection); }
+  void SetCommonAncestorForRangeInSelection()
+    { SetBoolFlag(NodeIsCommonAncestorForRangeInSelection); }
+  void ClearCommonAncestorForRangeInSelection()
+    { ClearBoolFlag(NodeIsCommonAncestorForRangeInSelection); }
+  bool IsDescendantOfCommonAncestorForRangeInSelection() const
+    { return GetBoolFlag(NodeIsDescendantOfCommonAncestorForRangeInSelection); }
+  void SetDescendantOfCommonAncestorForRangeInSelection()
+    { SetBoolFlag(NodeIsDescendantOfCommonAncestorForRangeInSelection); }
+  void ClearDescendantOfCommonAncestorForRangeInSelection()
+    { ClearBoolFlag(NodeIsDescendantOfCommonAncestorForRangeInSelection); }
+
+  void SetCCMarkedRoot(bool aValue)
+    { SetBoolFlag(NodeIsCCMarkedRoot, aValue); }
+  bool CCMarkedRoot() const { return GetBoolFlag(NodeIsCCMarkedRoot); }
+  void SetInCCBlackTree(bool aValue)
+    { SetBoolFlag(NodeIsCCBlackTree, aValue); }
+  bool InCCBlackTree() const { return GetBoolFlag(NodeIsCCBlackTree); }
+  void SetIsPurpleRoot(bool aValue)
+    { SetBoolFlag(NodeIsPurpleRoot, aValue); }
+  bool IsPurpleRoot() const { return GetBoolFlag(NodeIsPurpleRoot); }
+  bool MayHaveDOMMutationObserver()
+    { return GetBoolFlag(NodeMayHaveDOMMutationObserver); }
+  void SetMayHaveDOMMutationObserver()
+    { SetBoolFlag(NodeMayHaveDOMMutationObserver, true); }
+  bool HasListenerManager() { return HasFlag(NODE_HAS_LISTENERMANAGER); }
+  bool HasPointerLock() const { return GetBoolFlag(ElementHasPointerLock); }
+  void SetPointerLock() { SetBoolFlag(ElementHasPointerLock); }
+  void ClearPointerLock() { ClearBoolFlag(ElementHasPointerLock); }
+  bool MayHaveAnimations() { return GetBoolFlag(ElementHasAnimations); }
+  void SetMayHaveAnimations() { SetBoolFlag(ElementHasAnimations); }
+  void SetHasValidDir() { SetBoolFlag(NodeHasValidDirAttribute); }
+  void ClearHasValidDir() { ClearBoolFlag(NodeHasValidDirAttribute); }
+  bool HasValidDir() const { return GetBoolFlag(NodeHasValidDirAttribute); }
+  void SetHasFixedDir() {
+    MOZ_ASSERT(NodeType() != nsIDOMNode::TEXT_NODE,
+               "SetHasFixedDir on text node");
+    SetBoolFlag(NodeHasFixedDir);
+  }
+  void ClearHasFixedDir() {
+    MOZ_ASSERT(NodeType() != nsIDOMNode::TEXT_NODE,
+               "ClearHasFixedDir on text node");
+    ClearBoolFlag(NodeHasFixedDir);
+  }
+  bool HasFixedDir() const { return GetBoolFlag(NodeHasFixedDir); }
+  void SetHasDirAutoSet() {
+    MOZ_ASSERT(NodeType() != nsIDOMNode::TEXT_NODE,
+               "SetHasDirAutoSet on text node");
+    SetBoolFlag(NodeHasDirAutoSet);
+  }
+  void ClearHasDirAutoSet() {
+    MOZ_ASSERT(NodeType() != nsIDOMNode::TEXT_NODE,
+               "ClearHasDirAutoSet on text node");
+    ClearBoolFlag(NodeHasDirAutoSet);
+  }
+  bool HasDirAutoSet() const
+    { return GetBoolFlag(NodeHasDirAutoSet); }
+  void SetHasTextNodeDirectionalityMap() {
+    MOZ_ASSERT(NodeType() == nsIDOMNode::TEXT_NODE,
+               "SetHasTextNodeDirectionalityMap on non-text node");
+    SetBoolFlag(NodeHasTextNodeDirectionalityMap);
+  }
+  void ClearHasTextNodeDirectionalityMap() {
+    MOZ_ASSERT(NodeType() == nsIDOMNode::TEXT_NODE,
+               "ClearHasTextNodeDirectionalityMap on non-text node");
+    ClearBoolFlag(NodeHasTextNodeDirectionalityMap);
+  }
+  bool HasTextNodeDirectionalityMap() const {
+    MOZ_ASSERT(NodeType() == nsIDOMNode::TEXT_NODE,
+               "HasTextNodeDirectionalityMap on non-text node");
+    return GetBoolFlag(NodeHasTextNodeDirectionalityMap);
+  }
+
+  void SetHasDirAuto() { SetBoolFlag(NodeHasDirAuto); }
+  void ClearHasDirAuto() { ClearBoolFlag(NodeHasDirAuto); }
+  bool HasDirAuto() const { return GetBoolFlag(NodeHasDirAuto); }
+
+  void SetAncestorHasDirAuto() { SetBoolFlag(NodeAncestorHasDirAuto); }
+  void ClearAncestorHasDirAuto() { ClearBoolFlag(NodeAncestorHasDirAuto); }
+  bool AncestorHasDirAuto() const { return GetBoolFlag(NodeAncestorHasDirAuto); }
+
+  bool NodeOrAncestorHasDirAuto() const
+    { return HasDirAuto() || AncestorHasDirAuto(); }
+
+  void SetIsElementInStyleScope(bool aValue) {
+    MOZ_ASSERT(IsElement(), "SetIsInStyleScope on a non-Element node");
+    SetBoolFlag(ElementIsInStyleScope, aValue);
+  }
+  void SetIsElementInStyleScope() {
+    MOZ_ASSERT(IsElement(), "SetIsInStyleScope on a non-Element node");
+    SetBoolFlag(ElementIsInStyleScope);
+  }
+  void ClearIsElementInStyleScope() {
+    MOZ_ASSERT(IsElement(), "ClearIsInStyleScope on a non-Element node");
+    ClearBoolFlag(ElementIsInStyleScope);
+  }
+  bool IsElementInStyleScope() const { return GetBoolFlag(ElementIsInStyleScope); }
+
+  void SetIsScopedStyleRoot() { SetBoolFlag(ElementIsScopedStyleRoot); }
+  void ClearIsScopedStyleRoot() { ClearBoolFlag(ElementIsScopedStyleRoot); }
+  bool IsScopedStyleRoot() { return GetBoolFlag(ElementIsScopedStyleRoot); }
+  bool HasRelevantHoverRules() const { return GetBoolFlag(NodeHasRelevantHoverRules); }
+  void SetHasRelevantHoverRules() { SetBoolFlag(NodeHasRelevantHoverRules); }
+  void SetParserHasNotified() { SetBoolFlag(ParserHasNotified); };
+  bool HasParserNotified() { return GetBoolFlag(ParserHasNotified); }
+
+  void SetMayBeApzAware() { SetBoolFlag(MayBeApzAware); }
+  bool NodeMayBeApzAware() const
+  {
+    return GetBoolFlag(MayBeApzAware);
+  }
+protected:
+  void SetParentIsContent(bool aValue) { SetBoolFlag(ParentIsContent, aValue); }
+  void SetIsInDocument() { SetBoolFlag(IsInDocument); }
+  void SetNodeIsContent() { SetBoolFlag(NodeIsContent); }
+  void ClearInDocument() { ClearBoolFlag(IsInDocument); }
+  void SetIsElement() { SetBoolFlag(NodeIsElement); }
+  void SetHasID() { SetBoolFlag(ElementHasID); }
+  void ClearHasID() { ClearBoolFlag(ElementHasID); }
+  void SetMayHaveStyle() { SetBoolFlag(ElementMayHaveStyle); }
+  void SetHasName() { SetBoolFlag(ElementHasName); }
+  void ClearHasName() { ClearBoolFlag(ElementHasName); }
+  void SetMayHaveContentEditableAttr()
+    { SetBoolFlag(ElementMayHaveContentEditableAttr); }
+  bool HasExplicitBaseURI() const { return GetBoolFlag(NodeHasExplicitBaseURI); }
+  void SetHasExplicitBaseURI() { SetBoolFlag(NodeHasExplicitBaseURI); }
+  void SetHasLockedStyleStates() { SetBoolFlag(ElementHasLockedStyleStates); }
+  void ClearHasLockedStyleStates() { ClearBoolFlag(ElementHasLockedStyleStates); }
+  bool HasLockedStyleStates() const
+    { return GetBoolFlag(ElementHasLockedStyleStates); }
+  void SetHasWeirdParserInsertionMode() { SetBoolFlag(ElementHasWeirdParserInsertionMode); }
+  bool HasWeirdParserInsertionMode() const
+  { return GetBoolFlag(ElementHasWeirdParserInsertionMode); }
+  bool HandlingClick() const { return GetBoolFlag(NodeHandlingClick); }
+  void SetHandlingClick() { SetBoolFlag(NodeHandlingClick); }
+  void ClearHandlingClick() { ClearBoolFlag(NodeHandlingClick); }
+
+  void SetSubtreeRootPointer(nsINode* aSubtreeRoot)
+  {
+    NS_ASSERTION(aSubtreeRoot, "aSubtreeRoot can never be null!");
+    NS_ASSERTION(!(IsNodeOfType(eCONTENT) && IsInUncomposedDoc()) &&
+                 !IsInShadowTree(), "Shouldn't be here!");
+    mSubtreeRoot = aSubtreeRoot;
+  }
+
+  void ClearSubtreeRootPointer()
+  {
+    mSubtreeRoot = nullptr;
+  }
+
+public:
+  // Makes nsINode object to keep aObject alive.
+  void BindObject(nsISupports* aObject);
+  // After calling UnbindObject nsINode object doesn't keep
+  // aObject alive anymore.
+  void UnbindObject(nsISupports* aObject);
+
+  void GetBoundMutationObservers(nsTArray<RefPtr<nsDOMMutationObserver> >& aResult);
+
+  already_AddRefed<mozilla::dom::AccessibleNode> GetAccessibleNode();
+
+  /**
+   * Returns the length of this node, as specified at
+   * <http://dvcs.w3.org/hg/domcore/raw-file/tip/Overview.html#concept-node-length>
+   */
+  uint32_t Length() const;
+
+  void GetNodeName(mozilla::dom::DOMString& aNodeName)
+  {
+    const nsString& nodeName = NodeName();
+    aNodeName.SetStringBuffer(nsStringBuffer::FromString(nodeName),
+                              nodeName.Length());
+  }
+  MOZ_MUST_USE nsresult GetBaseURI(nsAString& aBaseURI) const;
+  // Return the base URI for the document.
+  // The returned value may differ if the document is loaded via XHR, and
+  // when accessed from chrome privileged script and
+  // from content privileged script for compatibility.
+  void GetBaseURIFromJS(nsAString& aBaseURI, mozilla::ErrorResult& aRv) const;
+  bool HasChildNodes() const
+  {
+    return HasChildren();
+  }
+  uint16_t CompareDocumentPosition(nsINode& aOther) const;
+  void GetNodeValue(nsAString& aNodeValue)
+  {
+    GetNodeValueInternal(aNodeValue);
+  }
+  void SetNodeValue(const nsAString& aNodeValue,
+                    mozilla::ErrorResult& aError)
+  {
+    SetNodeValueInternal(aNodeValue, aError);
+  }
+  virtual void GetNodeValueInternal(nsAString& aNodeValue);
+  virtual void SetNodeValueInternal(const nsAString& aNodeValue,
+                                    mozilla::ErrorResult& aError)
+  {
+    // The DOM spec says that when nodeValue is defined to be null "setting it
+    // has no effect", so we don't throw an exception.
+  }
+  void EnsurePreInsertionValidity(nsINode& aNewChild, nsINode* aRefChild,
+                                  mozilla::ErrorResult& aError);
+  nsINode* InsertBefore(nsINode& aNode, nsINode* aChild,
+                        mozilla::ErrorResult& aError)
+  {
+    return ReplaceOrInsertBefore(false, &aNode, aChild, aError);
+  }
+  nsINode* AppendChild(nsINode& aNode, mozilla::ErrorResult& aError)
+  {
+    return InsertBefore(aNode, nullptr, aError);
+  }
+  nsINode* ReplaceChild(nsINode& aNode, nsINode& aChild,
+                        mozilla::ErrorResult& aError)
+  {
+    return ReplaceOrInsertBefore(true, &aNode, &aChild, aError);
+  }
+  nsINode* RemoveChild(nsINode& aChild, mozilla::ErrorResult& aError);
+  already_AddRefed<nsINode> CloneNode(bool aDeep, mozilla::ErrorResult& aError);
+  bool IsSameNode(nsINode* aNode);
+  bool IsEqualNode(nsINode* aNode);
+  void GetNamespaceURI(nsAString& aNamespaceURI) const
+  {
+    mNodeInfo->GetNamespaceURI(aNamespaceURI);
+  }
+#ifdef MOZILLA_INTERNAL_API
+  void GetPrefix(nsAString& aPrefix)
+  {
+    mNodeInfo->GetPrefix(aPrefix);
+  }
+#endif
+  void GetLocalName(mozilla::dom::DOMString& aLocalName) const
+  {
+    const nsString& localName = LocalName();
+    if (localName.IsVoid()) {
+      aLocalName.SetNull();
+    } else {
+      aLocalName.SetStringBuffer(nsStringBuffer::FromString(localName),
+                                 localName.Length());
+    }
+  }
+
+  nsDOMAttributeMap* GetAttributes();
+  void SetUserData(JSContext* aCx, const nsAString& aKey,
+                   JS::Handle<JS::Value> aData,
+                   JS::MutableHandle<JS::Value> aRetval,
+                   mozilla::ErrorResult& aError);
+  void GetUserData(JSContext* aCx, const nsAString& aKey,
+                   JS::MutableHandle<JS::Value> aRetval,
+                   mozilla::ErrorResult& aError);
+
+  // Helper method to remove this node from its parent. This is not exposed
+  // through WebIDL.
+  // Only call this if the node has a parent node.
+  nsresult RemoveFromParent()
+  {
+    nsINode* parent = GetParentNode();
+    mozilla::ErrorResult rv;
+    parent->RemoveChild(*this, rv);
+    return rv.StealNSResult();
+  }
+
+  // ChildNode methods
+  mozilla::dom::Element* GetPreviousElementSibling() const;
+  mozilla::dom::Element* GetNextElementSibling() const;
+
+  void Before(const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
+  void After(const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
+  void ReplaceWith(const Sequence<OwningNodeOrString>& aNodes,
+                   ErrorResult& aRv);
+  /**
+   * Remove this node from its parent, if any.
+   */
+  void Remove();
+
+  // ParentNode methods
+  mozilla::dom::Element* GetFirstElementChild() const;
+  mozilla::dom::Element* GetLastElementChild() const;
+
+  void Prepend(const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
+  void Append(const Sequence<OwningNodeOrString>& aNodes, ErrorResult& aRv);
+
+  void GetBoxQuads(const BoxQuadOptions& aOptions,
+                   nsTArray<RefPtr<DOMQuad> >& aResult,
+                   mozilla::ErrorResult& aRv);
+
+  already_AddRefed<DOMQuad> ConvertQuadFromNode(DOMQuad& aQuad,
+                                                const TextOrElementOrDocument& aFrom,
+                                                const ConvertCoordinateOptions& aOptions,
+                                                ErrorResult& aRv);
+  already_AddRefed<DOMQuad> ConvertRectFromNode(DOMRectReadOnly& aRect,
+                                                const TextOrElementOrDocument& aFrom,
+                                                const ConvertCoordinateOptions& aOptions,
+                                                ErrorResult& aRv);
+  already_AddRefed<DOMPoint> ConvertPointFromNode(const DOMPointInit& aPoint,
+                                                  const TextOrElementOrDocument& aFrom,
+                                                  const ConvertCoordinateOptions& aOptions,
+                                                  ErrorResult& aRv);
+
+protected:
+
+  // Override this function to create a custom slots class.
+  // Must not return null.
+  virtual nsINode::nsSlots* CreateSlots();
+
+  bool HasSlots() const
+  {
+    return mSlots != nullptr;
+  }
+
+  nsSlots* GetExistingSlots() const
+  {
+    return mSlots;
+  }
+
+  nsSlots* Slots()
+  {
+    if (!HasSlots()) {
+      mSlots = CreateSlots();
+      MOZ_ASSERT(mSlots);
+    }
+    return GetExistingSlots();
+  }
+
+  nsTObserverArray<nsIMutationObserver*> *GetMutationObservers()
+  {
+    return HasSlots() ? &GetExistingSlots()->mMutationObservers : nullptr;
+  }
+
+  bool IsEditableInternal() const;
+  virtual bool IsEditableExternal() const
+  {
+    return IsEditableInternal();
+  }
+
+  virtual void GetTextContentInternal(nsAString& aTextContent,
+                                      mozilla::ErrorResult& aError);
+  virtual void SetTextContentInternal(const nsAString& aTextContent,
+                                      mozilla::ErrorResult& aError)
+  {
+  }
+
+#ifdef DEBUG
+  // Note: virtual so that IsInNativeAnonymousSubtree can be called accross
+  // module boundaries.
+  virtual void CheckNotNativeAnonymous() const;
+#endif
+
+  // These are just used to implement nsIDOMNode using
+  // NS_FORWARD_NSIDOMNODE_TO_NSINODE_HELPER and for quickstubs.
+  nsresult GetParentNode(nsIDOMNode** aParentNode);
+  nsresult GetParentElement(nsIDOMElement** aParentElement);
+  nsresult GetChildNodes(nsIDOMNodeList** aChildNodes);
+  nsresult GetFirstChild(nsIDOMNode** aFirstChild);
+  nsresult GetLastChild(nsIDOMNode** aLastChild);
+  nsresult GetPreviousSibling(nsIDOMNode** aPrevSibling);
+  nsresult GetNextSibling(nsIDOMNode** aNextSibling);
+  nsresult GetOwnerDocument(nsIDOMDocument** aOwnerDocument);
+  nsresult CompareDocumentPosition(nsIDOMNode* aOther,
+                                   uint16_t* aReturn);
+
+  void EnsurePreInsertionValidity1(nsINode& aNewChild, nsINode* aRefChild,
+                                   mozilla::ErrorResult& aError);
+  void EnsurePreInsertionValidity2(bool aReplace, nsINode& aNewChild,
+                                   nsINode* aRefChild,
+                                   mozilla::ErrorResult& aError);
+  nsresult ReplaceOrInsertBefore(bool aReplace, nsIDOMNode *aNewChild,
+                                 nsIDOMNode *aRefChild, nsIDOMNode **aReturn);
+  nsINode* ReplaceOrInsertBefore(bool aReplace, nsINode* aNewChild,
+                                 nsINode* aRefChild,
+                                 mozilla::ErrorResult& aError);
+  nsresult RemoveChild(nsIDOMNode* aOldChild, nsIDOMNode** aReturn);
+
+  /**
+   * Returns the Element that should be used for resolving namespaces
+   * on this node (ie the ownerElement for attributes, the documentElement for
+   * documents, the node itself for elements and for other nodes the parentNode
+   * if it is an element).
+   */
+  virtual mozilla::dom::Element* GetNameSpaceElement() = 0;
+
+  /**
+   * Most of the implementation of the nsINode RemoveChildAt method.
+   * Should only be called on document, element, and document fragment
+   * nodes.  The aChildArray passed in should be the one for |this|.
+   *
+   * @param aIndex The index to remove at.
+   * @param aNotify Whether to notify.
+   * @param aKid The kid at aIndex.  Must not be null.
+   * @param aChildArray The child array to work with.
+   * @param aMutationEvent whether to fire a mutation event for this removal.
+   */
+  void doRemoveChildAt(uint32_t aIndex, bool aNotify, nsIContent* aKid,
+                       nsAttrAndChildArray& aChildArray);
+
+  /**
+   * Most of the implementation of the nsINode InsertChildAt method.
+   * Should only be called on document, element, and document fragment
+   * nodes.  The aChildArray passed in should be the one for |this|.
+   *
+   * @param aKid The child to insert.
+   * @param aIndex The index to insert at.
+   * @param aNotify Whether to notify.
+   * @param aChildArray The child array to work with
+   */
+  nsresult doInsertChildAt(nsIContent* aKid, uint32_t aIndex,
+                           bool aNotify, nsAttrAndChildArray& aChildArray);
+
+  /**
+   * Parse the given selector string into an nsCSSSelectorList.
+   *
+   * A null return value with a non-failing aRv means the string only
+   * contained pseudo-element selectors.
+   *
+   * A failing aRv means the string was not a valid selector.
+   */
+  nsCSSSelectorList* ParseSelectorList(const nsAString& aSelectorString,
+                                       mozilla::ErrorResult& aRv);
+
+public:
+  /* Event stuff that documents and elements share.  This needs to be
+     NS_IMETHOD because some subclasses implement DOM methods with
+     this exact name and signature and then the calling convention
+     needs to match.
+
+     Note that we include DOCUMENT_ONLY_EVENT events here so that we
+     can forward all the document stuff to this implementation.
+  */
+#define EVENT(name_, id_, type_, struct_)                             \
+  mozilla::dom::EventHandlerNonNull* GetOn##name_();                  \
+  void SetOn##name_(mozilla::dom::EventHandlerNonNull* listener);
+#define TOUCH_EVENT EVENT
+#define DOCUMENT_ONLY_EVENT EVENT
+#include "mozilla/EventNameList.h"
+#undef DOCUMENT_ONLY_EVENT
+#undef TOUCH_EVENT
+#undef EVENT
+
+  bool HasServoData() {
+#ifdef MOZ_STYLO
+    return !!mServoData.Get();
+#else
+    MOZ_CRASH("Accessing servo node data in non-stylo build");
+#endif
+  }
+
+  void ClearServoData();
+
+protected:
+  static bool Traverse(nsINode *tmp, nsCycleCollectionTraversalCallback &cb);
+  static void Unlink(nsINode *tmp);
+
+  RefPtr<mozilla::dom::NodeInfo> mNodeInfo;
+
+  // mParent is an owning ref most of the time, except for the case of document
+  // nodes, so it cannot be represented by nsCOMPtr, so mark is as
+  // MOZ_OWNING_REF.
+  nsINode* MOZ_OWNING_REF mParent;
+
+private:
+  // Boolean flags.
+  uint32_t mBoolFlags;
+
+protected:
+  // These references are non-owning and safe, as they are managed by
+  // nsAttrAndChildArray.
+  nsIContent* MOZ_NON_OWNING_REF mNextSibling;
+  nsIContent* MOZ_NON_OWNING_REF mPreviousSibling;
+  // This reference is non-owning and safe, since in the case of documents,
+  // it is set to null when the document gets destroyed, and in the case of
+  // other nodes, the children keep the parents alive.
+  nsIContent* MOZ_NON_OWNING_REF mFirstChild;
+
+  union {
+    // Pointer to our primary frame.  Might be null.
+    nsIFrame* mPrimaryFrame;
+
+    // Pointer to the root of our subtree.  Might be null.
+    // This reference is non-owning and safe, since it either points to the
+    // object itself, or is reset by ClearSubtreeRootPointer.
+    nsINode* MOZ_NON_OWNING_REF mSubtreeRoot;
+  };
+
+  // Storage for more members that are usually not needed; allocated lazily.
+  nsSlots* mSlots;
+
+#ifdef MOZ_STYLO
+  // Per-node data managed by Servo.
+  mozilla::ServoCell<ServoNodeData*> mServoData;
+#endif
+};
+
+inline nsIDOMNode* GetAsDOMNode(nsINode* aNode)
+{
+  return aNode ? aNode->AsDOMNode() : nullptr;
+}
+
+// Useful inline function for getting a node given an nsIContent and an
+// nsIDocument.  Returns the first argument cast to nsINode if it is non-null,
+// otherwise returns the second (which may be null).  We use type variables
+// instead of nsIContent* and nsIDocument* because the actual types must be
+// known for the cast to work.
+template<class C, class D>
+inline nsINode* NODE_FROM(C& aContent, D& aDocument)
+{
+  if (aContent)
+    return static_cast<nsINode*>(aContent);
+  return static_cast<nsINode*>(aDocument);
+}
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsINode, NS_INODE_IID)
+
+inline nsISupports*
+ToSupports(nsINode* aPointer)
+{
+  return aPointer;
+}
+
+inline nsISupports*
+ToCanonicalSupports(nsINode* aPointer)
+{
+  return aPointer;
+}
+
+#define NS_FORWARD_NSIDOMNODE_TO_NSINODE_HELPER(...) \
+  NS_IMETHOD GetNodeName(nsAString& aNodeName) __VA_ARGS__ override \
+  { \
+    aNodeName = nsINode::NodeName(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetNodeValue(nsAString& aNodeValue) __VA_ARGS__ override \
+  { \
+    nsINode::GetNodeValue(aNodeValue); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD SetNodeValue(const nsAString& aNodeValue) __VA_ARGS__ override \
+  { \
+    mozilla::ErrorResult rv; \
+    nsINode::SetNodeValue(aNodeValue, rv); \
+    return rv.StealNSResult(); \
+  } \
+  NS_IMETHOD GetNodeType(uint16_t* aNodeType) __VA_ARGS__ override \
+  { \
+    *aNodeType = nsINode::NodeType(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetParentNode(nsIDOMNode** aParentNode) __VA_ARGS__ override \
+  { \
+    return nsINode::GetParentNode(aParentNode); \
+  } \
+  NS_IMETHOD GetParentElement(nsIDOMElement** aParentElement) __VA_ARGS__ override \
+  { \
+    return nsINode::GetParentElement(aParentElement); \
+  } \
+  NS_IMETHOD GetChildNodes(nsIDOMNodeList** aChildNodes) __VA_ARGS__ override \
+  { \
+    return nsINode::GetChildNodes(aChildNodes); \
+  } \
+  NS_IMETHOD GetFirstChild(nsIDOMNode** aFirstChild) __VA_ARGS__ override \
+  { \
+    return nsINode::GetFirstChild(aFirstChild); \
+  } \
+  NS_IMETHOD GetLastChild(nsIDOMNode** aLastChild) __VA_ARGS__ override \
+  { \
+    return nsINode::GetLastChild(aLastChild); \
+  } \
+  NS_IMETHOD GetPreviousSibling(nsIDOMNode** aPreviousSibling) __VA_ARGS__ override \
+  { \
+    return nsINode::GetPreviousSibling(aPreviousSibling); \
+  } \
+  NS_IMETHOD GetNextSibling(nsIDOMNode** aNextSibling) __VA_ARGS__ override \
+  { \
+    return nsINode::GetNextSibling(aNextSibling); \
+  } \
+  NS_IMETHOD GetOwnerDocument(nsIDOMDocument** aOwnerDocument) __VA_ARGS__ override \
+  { \
+    return nsINode::GetOwnerDocument(aOwnerDocument); \
+  } \
+  NS_IMETHOD InsertBefore(nsIDOMNode* aNewChild, nsIDOMNode* aRefChild, nsIDOMNode** aResult) __VA_ARGS__ override \
+  { \
+    return ReplaceOrInsertBefore(false, aNewChild, aRefChild, aResult); \
+  } \
+  NS_IMETHOD ReplaceChild(nsIDOMNode* aNewChild, nsIDOMNode* aOldChild, nsIDOMNode** aResult) __VA_ARGS__ override \
+  { \
+    return ReplaceOrInsertBefore(true, aNewChild, aOldChild, aResult); \
+  } \
+  NS_IMETHOD RemoveChild(nsIDOMNode* aOldChild, nsIDOMNode** aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::RemoveChild(aOldChild, aResult); \
+  } \
+  NS_IMETHOD AppendChild(nsIDOMNode* aNewChild, nsIDOMNode** aResult) __VA_ARGS__ override \
+  { \
+    return InsertBefore(aNewChild, nullptr, aResult); \
+  } \
+  NS_IMETHOD HasChildNodes(bool* aResult) __VA_ARGS__ override \
+  { \
+    *aResult = nsINode::HasChildNodes(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD CloneNode(bool aDeep, uint8_t aArgc, nsIDOMNode** aResult) __VA_ARGS__ override \
+  { \
+    if (aArgc == 0) { \
+      aDeep = true; \
+    } \
+    mozilla::ErrorResult rv; \
+    nsCOMPtr<nsINode> clone = nsINode::CloneNode(aDeep, rv); \
+    if (rv.Failed()) { \
+      return rv.StealNSResult(); \
+    } \
+    *aResult = clone.forget().take()->AsDOMNode(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD Normalize() __VA_ARGS__ override \
+  { \
+    nsINode::Normalize(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetNamespaceURI(nsAString& aNamespaceURI) __VA_ARGS__ override \
+  { \
+    nsINode::GetNamespaceURI(aNamespaceURI); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetPrefix(nsAString& aPrefix) __VA_ARGS__ override \
+  { \
+    nsINode::GetPrefix(aPrefix); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetLocalName(nsAString& aLocalName) __VA_ARGS__ override \
+  { \
+    aLocalName = nsINode::LocalName(); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD UnusedPlaceholder(bool* aResult) __VA_ARGS__ override \
+  { \
+    *aResult = false; \
+    return NS_OK; \
+  } \
+  NS_IMETHOD GetDOMBaseURI(nsAString& aBaseURI) __VA_ARGS__ override \
+  { \
+    return nsINode::GetBaseURI(aBaseURI); \
+  } \
+  NS_IMETHOD CompareDocumentPosition(nsIDOMNode* aOther, uint16_t* aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::CompareDocumentPosition(aOther, aResult); \
+  } \
+  NS_IMETHOD GetTextContent(nsAString& aTextContent) __VA_ARGS__ override \
+  { \
+    mozilla::ErrorResult rv; \
+    nsINode::GetTextContent(aTextContent, rv); \
+    return rv.StealNSResult(); \
+  } \
+  NS_IMETHOD SetTextContent(const nsAString& aTextContent) __VA_ARGS__ override \
+  { \
+    mozilla::ErrorResult rv; \
+    nsINode::SetTextContent(aTextContent, rv); \
+    return rv.StealNSResult(); \
+  } \
+  NS_IMETHOD LookupPrefix(const nsAString& aNamespaceURI, nsAString& aResult) __VA_ARGS__ override \
+  { \
+    nsINode::LookupPrefix(aNamespaceURI, aResult); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD IsDefaultNamespace(const nsAString& aNamespaceURI, bool* aResult) __VA_ARGS__ override \
+  { \
+    *aResult = nsINode::IsDefaultNamespace(aNamespaceURI); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD LookupNamespaceURI(const nsAString& aPrefix, nsAString& aResult) __VA_ARGS__ override \
+  { \
+    nsINode::LookupNamespaceURI(aPrefix, aResult); \
+    return NS_OK; \
+  } \
+  NS_IMETHOD IsEqualNode(nsIDOMNode* aArg, bool* aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::IsEqualNode(aArg, aResult); \
+  } \
+  NS_IMETHOD SetUserData(const nsAString& aKey, nsIVariant* aData, nsIVariant** aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::SetUserData(aKey, aData, aResult); \
+  } \
+  NS_IMETHOD GetUserData(const nsAString& aKey, nsIVariant** aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::GetUserData(aKey, aResult); \
+  } \
+  NS_IMETHOD Contains(nsIDOMNode* aOther, bool* aResult) __VA_ARGS__ override \
+  { \
+    return nsINode::Contains(aOther, aResult); \
+  }
+
+#define NS_FORWARD_NSIDOMNODE_TO_NSINODE \
+  NS_FORWARD_NSIDOMNODE_TO_NSINODE_HELPER(final)
+
+#define NS_FORWARD_NSIDOMNODE_TO_NSINODE_OVERRIDABLE \
+  NS_FORWARD_NSIDOMNODE_TO_NSINODE_HELPER()
+
+#endif /* nsINode_h___ */