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diff --git a/accessible/base/nsAccessiblePivot.h b/accessible/base/nsAccessiblePivot.h
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+++ b/accessible/base/nsAccessiblePivot.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 _nsAccessiblePivot_H_
+#define _nsAccessiblePivot_H_
+
+#include "nsIAccessiblePivot.h"
+
+#include "Accessible-inl.h"
+#include "nsTObserverArray.h"
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/Attributes.h"
+
+class RuleCache;
+
+/**
+ * Class represents an accessible pivot.
+ */
+class nsAccessiblePivot final : public nsIAccessiblePivot {
+ public:
+  typedef mozilla::a11y::Accessible Accessible;
+
+  explicit nsAccessiblePivot(Accessible* aRoot);
+
+  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsAccessiblePivot,
+                                           nsIAccessiblePivot)
+
+  NS_DECL_NSIACCESSIBLEPIVOT
+
+  /*
+   * A simple getter for the pivot's position.
+   */
+  Accessible* Position() { return mPosition; }
+
+  int32_t StartOffset() { return mStartOffset; }
+
+  int32_t EndOffset() { return mEndOffset; }
+
+ private:
+  ~nsAccessiblePivot();
+  nsAccessiblePivot() = delete;
+  nsAccessiblePivot(const nsAccessiblePivot&) = delete;
+  void operator=(const nsAccessiblePivot&) = delete;
+
+  /*
+   * Notify all observers on a pivot change. Return true if it has changed and
+   * observers have been notified.
+   */
+  bool NotifyOfPivotChange(Accessible* aOldAccessible, int32_t aOldStart,
+                           int32_t aOldEnd, PivotMoveReason aReason,
+                           TextBoundaryType aBoundaryType,
+                           bool aIsFromUserInput);
+
+  /*
+   * Check to see that the given accessible is a descendant of given ancestor
+   */
+  bool IsDescendantOf(Accessible* aAccessible, Accessible* aAncestor);
+
+  /*
+   * Search in preorder for the first accessible to match the rule.
+   */
+  Accessible* SearchForward(Accessible* aAccessible,
+                            nsIAccessibleTraversalRule* aRule,
+                            bool aSearchCurrent, nsresult* aResult);
+
+  /*
+   * Reverse search in preorder for the first accessible to match the rule.
+   */
+  Accessible* SearchBackward(Accessible* aAccessible,
+                             nsIAccessibleTraversalRule* aRule,
+                             bool aSearchCurrent, nsresult* aResult);
+
+  /*
+   * Get the effective root for this pivot, either the true root or modal root.
+   */
+  Accessible* GetActiveRoot() const {
+    if (mModalRoot) {
+      NS_ENSURE_FALSE(mModalRoot->IsDefunct(), mRoot);
+      return mModalRoot;
+    }
+
+    return mRoot;
+  }
+
+  /*
+   * Update the pivot, and notify observers. Return true if it moved.
+   */
+  bool MovePivotInternal(Accessible* aPosition, PivotMoveReason aReason,
+                         bool aIsFromUserInput);
+
+  /*
+   * Get initial node we should start a search from with a given rule.
+   *
+   * When we do a move operation from one position to another,
+   * the initial position can be inside of a subtree that is ignored by
+   * the given rule. We need to step out of the ignored subtree and start
+   * the search from there.
+   *
+   */
+  Accessible* AdjustStartPosition(Accessible* aAccessible, RuleCache& aCache,
+                                  uint16_t* aFilterResult, nsresult* aResult);
+
+  /*
+   * The root accessible.
+   */
+  RefPtr<Accessible> mRoot;
+
+  /*
+   * The temporary modal root accessible.
+   */
+  RefPtr<Accessible> mModalRoot;
+
+  /*
+   * The current pivot position.
+   */
+  RefPtr<Accessible> mPosition;
+
+  /*
+   * The text start offset ofthe pivot.
+   */
+  int32_t mStartOffset;
+
+  /*
+   * The text end offset ofthe pivot.
+   */
+  int32_t mEndOffset;
+
+  /*
+   * The list of pivot-changed observers.
+   */
+  nsTObserverArray<nsCOMPtr<nsIAccessiblePivotObserver> > mObservers;
+};
+
+#endif