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diff --git a/accessible/ipc/RemoteAccessible.h b/accessible/ipc/RemoteAccessible.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 mozilla_a11y_RemoteAccessible_h
+#define mozilla_a11y_RemoteAccessible_h
+
+#include "mozilla/a11y/Accessible.h"
+#include "mozilla/a11y/CacheConstants.h"
+#include "mozilla/a11y/HyperTextAccessibleBase.h"
+#include "mozilla/a11y/Role.h"
+#include "AccAttributes.h"
+#include "nsIAccessibleText.h"
+#include "nsIAccessibleTypes.h"
+#include "nsTArray.h"
+#include "nsRect.h"
+#include "LocalAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+class Attribute;
+class DocAccessibleParent;
+class RemoteAccessible;
+enum class RelationType;
+
+/**
+ * The class for an accessibility tree node that originated in the parent
+ * process.
+ */
+class RemoteAccessible : public Accessible, public HyperTextAccessibleBase {
+ public:
+  virtual ~RemoteAccessible() {
+    MOZ_ASSERT(!mWrapper);
+    MOZ_COUNT_DTOR(RemoteAccessible);
+  }
+
+  virtual bool IsRemote() const override { return true; }
+
+  void AddChildAt(uint32_t aIdx, RemoteAccessible* aChild) {
+    mChildren.InsertElementAt(aIdx, aChild);
+    if (IsHyperText()) {
+      InvalidateCachedHyperTextOffsets();
+    }
+  }
+
+  virtual uint32_t ChildCount() const override { return mChildren.Length(); }
+  RemoteAccessible* RemoteChildAt(uint32_t aIdx) const {
+    return mChildren.SafeElementAt(aIdx);
+  }
+  RemoteAccessible* RemoteFirstChild() const {
+    return mChildren.Length() ? mChildren[0] : nullptr;
+  }
+  RemoteAccessible* RemoteLastChild() const {
+    return mChildren.Length() ? mChildren[mChildren.Length() - 1] : nullptr;
+  }
+  RemoteAccessible* RemotePrevSibling() const {
+    if (IsDoc()) {
+      // The normal code path doesn't work for documents because the parent
+      // might be a local OuterDoc, but IndexInParent() will return 1.
+      // A document is always a single child of an OuterDoc anyway.
+      return nullptr;
+    }
+    int32_t idx = IndexInParent();
+    if (idx == -1) {
+      return nullptr;  // No parent.
+    }
+    return idx > 0 ? RemoteParent()->mChildren[idx - 1] : nullptr;
+  }
+  RemoteAccessible* RemoteNextSibling() const {
+    if (IsDoc()) {
+      // The normal code path doesn't work for documents because the parent
+      // might be a local OuterDoc, but IndexInParent() will return 1.
+      // A document is always a single child of an OuterDoc anyway.
+      return nullptr;
+    }
+    int32_t idx = IndexInParent();
+    if (idx == -1) {
+      return nullptr;  // No parent.
+    }
+    MOZ_ASSERT(idx >= 0);
+    size_t newIdx = idx + 1;
+    return newIdx < RemoteParent()->mChildren.Length()
+               ? RemoteParent()->mChildren[newIdx]
+               : nullptr;
+  }
+
+  // Accessible hierarchy method overrides
+
+  virtual Accessible* Parent() const override { return RemoteParent(); }
+
+  virtual Accessible* ChildAt(uint32_t aIndex) const override {
+    return RemoteChildAt(aIndex);
+  }
+
+  virtual Accessible* NextSibling() const override {
+    return RemoteNextSibling();
+  }
+
+  virtual Accessible* PrevSibling() const override {
+    return RemotePrevSibling();
+  }
+
+  // XXX evaluate if this is fast enough.
+  virtual int32_t IndexInParent() const override {
+    RemoteAccessible* parent = RemoteParent();
+    if (!parent) {
+      return -1;
+    }
+    return parent->mChildren.IndexOf(
+        static_cast<const RemoteAccessible*>(this));
+  }
+  virtual uint32_t EmbeddedChildCount() override;
+  virtual int32_t IndexOfEmbeddedChild(Accessible* aChild) override;
+  virtual Accessible* EmbeddedChildAt(uint32_t aChildIdx) override;
+
+  void Shutdown();
+
+  void SetChildDoc(DocAccessibleParent* aChildDoc);
+  void ClearChildDoc(DocAccessibleParent* aChildDoc);
+
+  /**
+   * Remove The given child.
+   */
+  void RemoveChild(RemoteAccessible* aChild) {
+    mChildren.RemoveElement(aChild);
+    if (IsHyperText()) {
+      InvalidateCachedHyperTextOffsets();
+    }
+  }
+
+  /**
+   * Return the proxy for the parent of the wrapped accessible.
+   */
+  RemoteAccessible* RemoteParent() const;
+
+  LocalAccessible* OuterDocOfRemoteBrowser() const;
+
+  /**
+   * Get the role of the accessible we're proxying.
+   */
+  virtual role Role() const override { return mRole; }
+
+  /**
+   * Return true if this is an embedded object.
+   */
+  bool IsEmbeddedObject() const { return !IsText(); }
+
+  virtual bool IsLink() const override {
+    if (IsHTMLLink()) {
+      // XXX: HTML links always return true for IsLink.
+      return true;
+    }
+
+    if (IsText()) {
+      return false;
+    }
+
+    if (Accessible* parent = Parent()) {
+      return parent->IsHyperText();
+    }
+
+    return false;
+  }
+
+  virtual bool HasNumericValue() const override {
+    // XXX: We combine the aria and native "has numeric value" field
+    // when we serialize the local accessible into eNumericValue.
+    return HasGenericType(eNumericValue);
+  }
+
+  // Methods that potentially access a cache.
+
+  virtual ENameValueFlag Name(nsString& aName) const override;
+  virtual void Description(nsString& aDescription) const override;
+  virtual void Value(nsString& aValue) const override;
+
+  virtual double CurValue() const override;
+  virtual double MinValue() const override;
+  virtual double MaxValue() const override;
+  virtual double Step() const override;
+  virtual bool SetCurValue(double aValue) override;
+
+  virtual Accessible* ChildAtPoint(
+      int32_t aX, int32_t aY,
+      LocalAccessible::EWhichChildAtPoint aWhichChild) override;
+
+  virtual LayoutDeviceIntRect Bounds() const override;
+
+  virtual nsRect BoundsInAppUnits() const override;
+
+  virtual Relation RelationByType(RelationType aType) const override;
+
+  virtual uint64_t State() override;
+
+  virtual already_AddRefed<AccAttributes> Attributes() override;
+
+  virtual nsAtom* TagName() const override;
+
+  virtual already_AddRefed<nsAtom> InputType() const override;
+
+  virtual already_AddRefed<nsAtom> DisplayStyle() const override;
+
+  virtual float Opacity() const override;
+
+  virtual void LiveRegionAttributes(nsAString* aLive, nsAString* aRelevant,
+                                    Maybe<bool>* aAtomic,
+                                    nsAString* aBusy) const override;
+
+  virtual Maybe<bool> ARIASelected() const override;
+
+  virtual uint8_t ActionCount() const override;
+
+  virtual void ActionNameAt(uint8_t aIndex, nsAString& aName) override;
+
+  virtual bool DoAction(uint8_t aIndex) const override;
+
+  virtual KeyBinding AccessKey() const override;
+
+  virtual void SelectionRanges(nsTArray<TextRange>* aRanges) const override;
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual bool RemoveFromSelection(
+      int32_t aSelectionNum) override;
+
+  virtual Maybe<int32_t> GetIntARIAAttr(nsAtom* aAttrName) const override;
+
+  virtual void Language(nsAString& aLocale) override;
+
+  //////////////////////////////////////////////////////////////////////////////
+  // EditableTextAccessible
+
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void ReplaceText(
+      const nsAString& aText) override;
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void InsertText(
+      const nsAString& aText, int32_t aPosition) override;
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void CopyText(int32_t aStartPos,
+                                                    int32_t aEndPos) override;
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void CutText(int32_t aStartPos,
+                                                   int32_t aEndPos) override;
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY virtual void DeleteText(int32_t aStartPos,
+                                                      int32_t aEndPos) override;
+  MOZ_CAN_RUN_SCRIPT virtual void PasteText(int32_t aPosition) override;
+
+  //////////////////////////////////////////////////////////////////////////////
+  // SelectAccessible
+
+  virtual void SelectedItems(nsTArray<Accessible*>* aItems) override;
+
+  virtual uint32_t SelectedItemCount() override;
+
+  virtual Accessible* GetSelectedItem(uint32_t aIndex) override;
+
+  virtual bool IsItemSelected(uint32_t aIndex) override;
+
+  virtual bool AddItemToSelection(uint32_t aIndex) override;
+
+  virtual bool RemoveItemFromSelection(uint32_t aIndex) override;
+
+  virtual bool SelectAll() override;
+
+  virtual bool UnselectAll() override;
+
+  virtual void TakeSelection() override;
+
+  virtual void SetSelected(bool aSelect) override;
+
+  // Methods that interact with content.
+
+  virtual void TakeFocus() const override;
+  virtual void ScrollTo(uint32_t aHow) const override;
+  virtual void SetCaretOffset(int32_t aOffset) override;
+
+  /**
+   * Allow the platform to store a pointers worth of data on us.
+   */
+  uintptr_t GetWrapper() const { return mWrapper; }
+  void SetWrapper(uintptr_t aWrapper) { mWrapper = aWrapper; }
+
+  virtual uint64_t ID() const override { return mID; }
+
+  /**
+   * Return the document containing this proxy, or the proxy itself if it is a
+   * document.
+   */
+  DocAccessibleParent* Document() const { return mDoc; }
+
+  DocAccessibleParent* AsDoc() const { return IsDoc() ? mDoc : nullptr; }
+
+  void ApplyCache(CacheUpdateType aUpdateType, AccAttributes* aFields);
+
+  void UpdateStateCache(uint64_t aState, bool aEnabled) {
+    if (aState & kRemoteCalculatedStates) {
+      return;
+    }
+    uint64_t state = 0;
+    if (mCachedFields) {
+      if (auto oldState =
+              mCachedFields->GetAttribute<uint64_t>(CacheKey::State)) {
+        state = *oldState;
+      }
+    } else {
+      mCachedFields = new AccAttributes();
+    }
+    if (aEnabled) {
+      state |= aState;
+    } else {
+      state &= ~aState;
+    }
+    mCachedFields->SetAttribute(CacheKey::State, state);
+  }
+
+  void InvalidateGroupInfo();
+
+  virtual void AppendTextTo(nsAString& aText, uint32_t aStartOffset = 0,
+                            uint32_t aLength = UINT32_MAX) override;
+
+  virtual bool TableIsProbablyForLayout();
+
+  /**
+   * Iterates through each atom in kRelationTypeAtoms, checking to see
+   * if it is present in aFields. If it is present (or if aFields contains
+   * a DeleteEntry() for this atom) and mCachedFields is initialized,
+   * fetches the old rel targets and removes their existing reverse relations
+   * stored in mReverseRelations.
+   * Returns an array of bools where the ith array entry corresponds
+   * to whether or not the rel at the ith entry of kRelationTypeAtoms
+   * requires a post-processing update.
+   */
+  nsTArray<bool> PreProcessRelations(AccAttributes* aFields);
+
+  /**
+   * Takes in the array returned from PreProcessRelations.
+   * For each entry requiring an update, fetches the new relation
+   * targets stored in mCachedFields and appropriately
+   * updates their reverse relations in mReverseRelations.
+   */
+  void PostProcessRelations(const nsTArray<bool>& aToUpdate);
+
+  /**
+   * This method is called during shutdown, before we clear our
+   * reverse rel map from the document's mReverseRelations cache.
+   * Here, we traverse our reverse relations, removing our ID from
+   * the corresponding forward relation's target list. This ensures
+   * the stored forward relations do not reference defunct accessibles.
+   */
+  void PruneRelationsOnShutdown();
+
+  uint32_t GetCachedTextLength();
+  Maybe<const nsTArray<int32_t>&> GetCachedTextLines();
+  nsRect GetCachedCharRect(int32_t aOffset);
+  RefPtr<const AccAttributes> GetCachedTextAttributes();
+  RefPtr<const AccAttributes> GetCachedARIAAttributes() const;
+
+  nsString GetCachedHTMLNameAttribute() const;
+
+  virtual HyperTextAccessibleBase* AsHyperTextBase() override {
+    return IsHyperText() ? static_cast<HyperTextAccessibleBase*>(this)
+                         : nullptr;
+  }
+
+  virtual TableAccessible* AsTable() override;
+  virtual TableCellAccessible* AsTableCell() override;
+
+  virtual void DOMNodeID(nsString& aID) const override;
+
+  virtual void ScrollToPoint(uint32_t aScrollType, int32_t aX,
+                             int32_t aY) override;
+
+#if !defined(XP_WIN)
+  void Announce(const nsString& aAnnouncement, uint16_t aPriority);
+#endif  // !defined(XP_WIN)
+
+  // HyperTextAccessibleBase
+  virtual already_AddRefed<AccAttributes> DefaultTextAttributes() override;
+
+  virtual void ScrollSubstringToPoint(int32_t aStartOffset, int32_t aEndOffset,
+                                      uint32_t aCoordinateType, int32_t aX,
+                                      int32_t aY) override;
+
+  /**
+   * Invalidate cached HyperText offsets. This should be called whenever a
+   * child is added or removed or the text of a text leaf child is changed.
+   * Although GetChildOffset can either fully or partially invalidate the
+   * offsets cache, calculating which offset to invalidate is not worthwhile
+   * because a client might not even query offsets. This is in contrast to
+   * LocalAccessible, where the offsets are always needed to fire text change
+   * events. For RemoteAccessible, it's cheaper overall to just rebuild the
+   * offsets cache when a client next needs it.
+   */
+  void InvalidateCachedHyperTextOffsets() {
+    if (mCachedFields) {
+      mCachedFields->Remove(CacheKey::HyperTextOffsets);
+    }
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf);
+  virtual size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf);
+
+ protected:
+  RemoteAccessible(uint64_t aID, DocAccessibleParent* aDoc, role aRole,
+                   AccType aType, AccGenericType aGenericTypes,
+                   uint8_t aRoleMapEntryIndex)
+      : Accessible(aType, aGenericTypes, aRoleMapEntryIndex),
+        mParent(kNoParent),
+        mDoc(aDoc),
+        mWrapper(0),
+        mID(aID),
+        mCachedFields(nullptr),
+        mRole(aRole) {
+    MOZ_COUNT_CTOR(RemoteAccessible);
+  }
+
+  explicit RemoteAccessible(DocAccessibleParent* aThisAsDoc)
+      : mParent(kNoParent),
+        mDoc(aThisAsDoc),
+        mWrapper(0),
+        mID(0),
+        mCachedFields(nullptr),
+        mRole(roles::DOCUMENT) {
+    mGenericTypes = eDocument | eHyperText;
+    MOZ_COUNT_CTOR(RemoteAccessible);
+  }
+
+ protected:
+  void SetParent(RemoteAccessible* aParent);
+  Maybe<nsRect> RetrieveCachedBounds() const;
+  bool ApplyTransform(nsRect& aCumulativeBounds) const;
+  bool ApplyScrollOffset(nsRect& aBounds) const;
+  void ApplyCrossDocOffset(nsRect& aBounds) const;
+  LayoutDeviceIntRect BoundsWithOffset(
+      Maybe<nsRect> aOffset, bool aBoundsAreForHittesting = false) const;
+  bool IsFixedPos() const;
+  bool IsOverflowHidden() const;
+
+  /**
+   * Returns true if an accessible's frame has no scrollable overflow, and
+   * false otherwise.
+   * Does not return true for partially clipped accessibles.
+   */
+  bool IsClipped() const;
+
+  /**
+   * Checks if our hittesting match has any clipped children and, if so
+   * descends it and subsequent TEXT_CONTAINERs in search of a text leaf.
+   * We do this because some sites use clipping to hide text that is only
+   * visible to a11y, while displaying a visual version of the same text on
+   * the web page. We want a hittest of the visible text to resolve to the
+   * hidden, a11y-only text node.
+   */
+  RemoteAccessible* DoFuzzyHittesting();
+
+  // This function is used exclusively for hit testing.
+  bool ContainsPoint(int32_t aX, int32_t aY);
+
+  virtual void ARIAGroupPosition(int32_t* aLevel, int32_t* aSetSize,
+                                 int32_t* aPosInSet) const override;
+
+  virtual AccGroupInfo* GetGroupInfo() const override;
+
+  virtual AccGroupInfo* GetOrCreateGroupInfo() override;
+
+  virtual void GetPositionAndSetSize(int32_t* aPosInSet,
+                                     int32_t* aSetSize) override;
+
+  virtual bool HasPrimaryAction() const override;
+
+  nsAtom* GetPrimaryAction() const;
+
+  virtual nsTArray<int32_t>& GetCachedHyperTextOffsets() override;
+
+ private:
+  uintptr_t mParent;
+  static const uintptr_t kNoParent = UINTPTR_MAX;
+
+  friend DocAccessibleParent;
+  friend TextLeafPoint;
+  friend HyperTextAccessibleBase;
+  friend class xpcAccessible;
+  friend class CachedTableCellAccessible;
+#ifdef XP_WIN
+  friend class sdnAccessible;
+#endif
+
+  nsTArray<RemoteAccessible*> mChildren;
+  DocAccessibleParent* mDoc;
+  uintptr_t mWrapper;
+  uint64_t mID;
+
+ protected:
+  virtual const Accessible* Acc() const override { return this; }
+
+  RefPtr<AccAttributes> mCachedFields;
+
+  // XXX DocAccessibleParent gets to change this to change the role of
+  // documents.
+  role mRole : 27;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// RemoteAccessible downcasting method
+
+inline RemoteAccessible* Accessible::AsRemote() {
+  return IsRemote() ? static_cast<RemoteAccessible*>(this) : nullptr;
+}
+
+}  // namespace a11y
+}  // namespace mozilla
+
+#endif