wm: Change the DispatcherClient interface.

ui/wm/public/dispatcher_client.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 UI_WM_PUBLIC_DISPATCHER_CLIENT_H_
 #define UI_WM_PUBLIC_DISPATCHER_CLIENT_H_
 
+#include "base/callback_forward.h"
 #include "base/message_loop/message_pump_dispatcher.h"
 #include "ui/aura/aura_export.h"
 
 namespace aura {
 class Window;
 namespace client {
 
 // An interface implemented by an object which handles nested dispatchers.
 class AURA_EXPORT DispatcherClient {
  public:
-  virtual void RunWithDispatcher(base::MessagePumpDispatcher* dispatcher) = 0;
-
-  virtual void QuitNestedMessageLoop() = 0;
+  virtual void RunWithDispatcher(base::MessagePumpDispatcher* dispatcher,
+                                 base::Closure* quit_closure) = 0;

[sky, 2014/05/27 17:19:38]

It seems more natural to use a scoping object for this. Basically the same thing
as RunLoop. You create the RunLoop, run it, then destroy or quit it to cancel
the runloop. If you did that you could make RunWithDispatcher protected and
friend the RunLoop class.

[sadrul, 2014/05/27 17:37:14]

Do you mean something like:

  DispatcherClient* client = ...;
  DispatcherRunLoop run_loop = client->CreateNestedRunLoop();
  quit_closure_ = run_loop.QuitClosure();
  run_loop.Run();

?

 };
 
 AURA_EXPORT void SetDispatcherClient(Window* root_window,
                                      DispatcherClient* client);
 AURA_EXPORT DispatcherClient* GetDispatcherClient(Window* root_window);
 
 }  // namespace client
 }  // namespace aura
 
 #endif  // UI_WM_PUBLIC_DISPATCHER_CLIENT_H_