Change AckEvent into request / response

mojo/examples/aura_demo/window_tree_host_mojo.h

 // Copyright (c) 2013 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 MOJO_EXAMPLES_AURA_DEMO_WINDOW_TREE_HOST_MOJO_H_
 #define MOJO_EXAMPLES_AURA_DEMO_WINDOW_TREE_HOST_MOJO_H_
 
 #include "base/bind.h"
 #include "mojo/public/bindings/remote_ptr.h"
 #include "mojo/services/native_viewport/native_viewport.mojom.h"
@@ skipping 42 matching lines @@
   virtual void MoveCursorToNative(const gfx::Point& location) OVERRIDE;
   virtual void OnCursorVisibilityChangedNative(bool show) OVERRIDE;
 
   // ui::EventSource:
   virtual ui::EventProcessor* GetEventProcessor() OVERRIDE;
 
   // Overridden from NativeViewportClient:
   virtual void OnCreated() OVERRIDE;
   virtual void OnDestroyed() OVERRIDE;
   virtual void OnBoundsChanged(const Rect& bounds) OVERRIDE;
-  virtual void OnEvent(const Event& event) OVERRIDE;
+  virtual void OnEvent(const Event& event,
+                       const mojo::Callback<void()>& callback) OVERRIDE;
 
   static ui::ContextFactory* context_factory_;
 
   ScopedMessagePipeHandle gles2_handle_;
   RemotePtr<NativeViewport> native_viewport_;
   base::Callback<void()> compositor_created_callback_;
 
   gfx::Rect bounds_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMojo);
 };
 
 }  // namespace examples
 }  // namespace mojo
 
 #endif  // MOJO_EXAMPLES_AURA_DEMO_WINDOW_TREE_HOST_MOJO_H_