Refactors event dispatching of NativeViewport into its own interface

examples/surfaces_app/surfaces_app.cc

 // 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.
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "cc/surfaces/surface_id_allocator.h"
 #include "examples/surfaces_app/child.mojom.h"
@@ skipping 87 matching lines @@
     Draw(10);
   }
 
   // SurfaceClient implementation.
   virtual void ReturnResources(Array<ReturnedResourcePtr> resources) override {
     DCHECK(!resources.size());
   }
   // NativeViewportClient implementation.
   virtual void OnSizeChanged(mojo::SizePtr size) override {}
   virtual void OnDestroyed() override {}
-  virtual void OnEvent(mojo::EventPtr event,
-                       const mojo::Callback<void()>& callback) override {
-    callback.Run();
-  }
 
  private:
   void OnCreatedNativeViewport(uint64_t native_viewport_id) {}
 
   SurfacesServicePtr surfaces_service_;
   SurfacePtr surface_;
   cc::SurfaceId onscreen_id_;
   scoped_ptr<cc::SurfaceIdAllocator> allocator_;
   scoped_ptr<Embedder> embedder_;
   ChildPtr child_one_;
@@ skipping 10 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(SurfacesApp);
 };
 
 }  // namespace examples
 }  // namespace mojo
 
 MojoResult MojoMain(MojoHandle shell_handle) {
   mojo::ApplicationRunnerChromium runner(new mojo::examples::SurfacesApp);
   return runner.Run(shell_handle);
 }