Reset accessibility if it gets out of sync.

content/renderer/accessibility/renderer_accessibility_complete.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
 #define CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 52 matching lines @@
  private:
   // Handlers for messages from the browser to the renderer.
   void OnDoDefaultAction(int acc_obj_id);
   void OnEventsAck();
   void OnChangeScrollPosition(int acc_obj_id, int scroll_x, int scroll_y);
   void OnScrollToMakeVisible(int acc_obj_id, gfx::Rect subfocus);
   void OnScrollToPoint(int acc_obj_id, gfx::Point point);
   void OnSetFocus(int acc_obj_id);
   void OnSetTextSelection(int acc_obj_id, int start_offset, int end_offset);
   void OnHitTest(gfx::Point point);
+  void OnReset(int reset_token);
   void OnFatalError();
 
   // Events from Blink are collected until they are ready to be
   // sent to the browser.
   std::vector<AccessibilityHostMsg_EventParams> pending_events_;
 
   // The adapter that exposes Blink's accessibility tree to AXTreeSerializer.
   BlinkAXTreeSource tree_source_;
 
   // The serializer that sends accessibility messages to the browser process.
   ui::AXTreeSerializer<blink::WebAXObject> serializer_;
 
   // Current location of every object, so we can detect when it moves.
   base::hash_map<int, gfx::Rect> locations_;
 
   // The most recently observed scroll offset of the root document element.
   // TODO(dmazzoni): remove once https://bugs.webkit.org/show_bug.cgi?id=73460
   // is fixed.
   gfx::Size last_scroll_offset_;
 
   // Set if we are waiting for an accessibility event ack.
   bool ack_pending_;
 
+  // Nonzero if the browser requested we reset the accessibility state.
+  // We need to return this token in the next IPC.
+  int reset_token_;
+
   // So we can queue up tasks to be executed later.
   base::WeakPtrFactory<RendererAccessibilityComplete> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererAccessibilityComplete);
 };
 
 #endif  // CONTENT_RENDERER_ACCESSIBILITY_RENDERER_ACCESSIBILITY_COMPLETE_H_
 
 }  // namespace content