Use StrongBinding instead of InterfaceImpl in wm event dispatcher

services/window_manager/native_viewport_event_dispatcher_impl.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 "services/window_manager/native_viewport_event_dispatcher_impl.h"
 
 #include "mojo/converters/input_events/input_events_type_converters.h"
 #include "services/window_manager/view_event_dispatcher.h"
 #include "services/window_manager/window_manager_app.h"
 
 namespace window_manager {
 
 NativeViewportEventDispatcherImpl::NativeViewportEventDispatcherImpl(
-    WindowManagerApp* app)
-    : app_(app) {
+    WindowManagerApp* app,
+    mojo::InterfaceRequest<mojo::NativeViewportEventDispatcher> request)
+    : app_(app), binding_(this, request.Pass()) {
 }
 NativeViewportEventDispatcherImpl::~NativeViewportEventDispatcherImpl() {
 }
 
 ui::EventProcessor* NativeViewportEventDispatcherImpl::GetEventProcessor() {
   return app_->event_dispatcher();
 }
 
 void NativeViewportEventDispatcherImpl::OnEvent(
     mojo::EventPtr event,
     const mojo::Callback<void()>& callback) {
   scoped_ptr<ui::Event> ui_event = event.To<scoped_ptr<ui::Event>>();
 
   if (ui_event)
     SendEventToProcessor(ui_event.get());
 
   callback.Run();
 }
 
 }  // namespace window_manager