Suppress accessibility events when user is navigating away.

content/browser/accessibility/browser_accessibility_manager.h

Index: content/browser/accessibility/browser_accessibility_manager.h
diff --git a/content/browser/accessibility/browser_accessibility_manager.h b/content/browser/accessibility/browser_accessibility_manager.h
index c0e59fa1d68548408bbe583a39e5ec8faf056fb4..e6b26216d75979c2236ceb9d6e55faf3ee346df1 100644
--- a/content/browser/accessibility/browser_accessibility_manager.h
+++ b/content/browser/accessibility/browser_accessibility_manager.h
@@ -144,6 +144,11 @@ class CONTENT_EXPORT BrowserAccessibilityManager : public ui::AXTreeDelegate {
   // view lost focus.
   virtual void OnWindowBlurred();
 
+  // Notify the accessibility manager about page navigation.
+  void UserIsNavigatingAway(bool is_reload);
+  void NavigationSucceeded();
+  void NavigationFailed();
+
   // Called to notify the accessibility manager that a mouse down event
   // occurred in the tab.
   void GotMouseDown();
@@ -299,6 +304,9 @@ class CONTENT_EXPORT BrowserAccessibilityManager : public ui::AXTreeDelegate {
   // A mapping from a node id to its wrapper of type BrowserAccessibility.
   base::hash_map<int32, BrowserAccessibility*> id_wrapper_map_;
 
+  // True if the user has initiated a navigation to another page.
+  bool user_is_navigating_away_;
+
   // The on-screen keyboard state.
   OnScreenKeyboardState osk_state_;