Use the default dispatcher where possible for nested message loops.

ash/accelerators/nested_dispatcher_controller.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 ASH_ACCELERATORS_NESTED_DISPATCHER_CONTROLLER_H_
 #define ASH_ACCELERATORS_NESTED_DISPATCHER_CONTROLLER_H_
 
 #include "ash/ash_export.h"
+#include "base/callback.h"
 #include "base/message_loop/message_loop.h"
 #include "ui/aura/client/dispatcher_client.h"
 #include "ui/aura/window.h"
 
 namespace ash {
 
 // Creates a dispatcher which wraps another dispatcher.
 // The outer dispatcher runs first and performs ash specific handling.
 // If it does not consume the event it forwards the event to the nested
 // dispatcher.
 class ASH_EXPORT NestedDispatcherController
     : public aura::client::DispatcherClient {
  public:
   NestedDispatcherController();
   virtual ~NestedDispatcherController();
 
+  // aura::client::DispatcherClient:
   virtual void RunWithDispatcher(base::MessagePumpDispatcher* dispatcher,
                                  aura::Window* associated_window) OVERRIDE;
+  virtual void QuitNestedMessageLoop() OVERRIDE;
 
  private:
+  base::Closure quit_closure_;
+
   DISALLOW_COPY_AND_ASSIGN(NestedDispatcherController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_ACCELERATORS_NESTED_DISPATCHER_CONTROLLER_H_