Refactors event dispatching of NativeViewport into its own interface

mojo/services/window_manager/native_viewport_event_dispatcher_impl.h

+// 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.
+
+#ifndef MOJO_SERVICES_WINDOW_MANAGER_NATIVE_VIEWPORT_EVENT_DISPATCHER_IMPL_H_
+#define MOJO_SERVICES_WINDOW_MANAGER_NATIVE_VIEWPORT_EVENT_DISPATCHER_IMPL_H_
+
+#include "base/basictypes.h"
+#include "mojo/services/public/interfaces/native_viewport/native_viewport.mojom.h"
+
+namespace mojo {
+
+class WindowManagerApp;
+
+class NativeViewportEventDispatcherImpl
+    : public InterfaceImpl<NativeViewportEventDispatcher> {
+ public:
+  explicit NativeViewportEventDispatcherImpl(WindowManagerApp* app);
+  ~NativeViewportEventDispatcherImpl() override;
+
+ private:
+  // NativeViewportEventDispatcher:
+  void OnEvent(mojo::EventPtr event,
+               const mojo::Callback<void()>& callback) override;
+
+  WindowManagerApp* app_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeViewportEventDispatcherImpl);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_SERVICES_WINDOW_MANAGER_NATIVE_VIEWPORT_EVENT_DISPATCHER_IMPL_H_