Revert 258077 "Remove PrepareForShutdown"

trunk/src/ui/aura/window_event_dispatcher.h

 // Copyright 2014 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 UI_AURA_WINDOW_EVENT_DISPATCHER_H_
 #define UI_AURA_WINDOW_EVENT_DISPATCHER_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 47 matching lines @@
   Window* window() { return host()->window(); }
   const Window* window() const { return host()->window(); }
   WindowTreeHost* host() {
     return const_cast<WindowTreeHost*>(
         const_cast<const WindowEventDispatcher*>(this)->host());
   }
   const WindowTreeHost* host() const { return host_; }
   Window* mouse_pressed_handler() { return mouse_pressed_handler_; }
   Window* mouse_moved_handler() { return mouse_moved_handler_; }
 
+  // Stop listening events in preparation for shutdown.
+  void PrepareForShutdown();
+
   // Repost event for re-processing. Used when exiting context menus.
   // We only support the ET_MOUSE_PRESSED and ET_GESTURE_TAP_DOWN event
   // types (although the latter is currently a no-op).
   void RepostEvent(const ui::LocatedEvent& event);
 
   // Invoked when the mouse events get enabled or disabled.
   void OnMouseEventsEnableStateChanged(bool enabled);
 
   void DispatchCancelModeEvent();
 
@@ skipping 177 matching lines @@
 
   // Used to schedule DispatchHeldEvents() when |move_hold_count_| goes to 0.
   base::WeakPtrFactory<WindowEventDispatcher> held_event_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowEventDispatcher);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_EVENT_DISPATCHER_H_