Reset accessibility if it gets out of sync.

content/renderer/accessibility/renderer_accessibility_complete.h

Index: content/renderer/accessibility/renderer_accessibility_complete.h
diff --git a/content/renderer/accessibility/renderer_accessibility_complete.h b/content/renderer/accessibility/renderer_accessibility_complete.h
index 81b9dcb101b18da0076e82b1b91323af4c9a28ce..3f33c088a57028f70475913207da3760e84ab3a7 100644
--- a/content/renderer/accessibility/renderer_accessibility_complete.h
+++ b/content/renderer/accessibility/renderer_accessibility_complete.h
@@ -70,6 +70,7 @@ class CONTENT_EXPORT RendererAccessibilityComplete
   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
@@ -93,6 +94,10 @@ class CONTENT_EXPORT RendererAccessibilityComplete
   // 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_;