[DRAFT] Add new default stylesheet for platform apps.

chrome/renderer/extensions/platform_app_dispatcher.h

+// Copyright (c) 2011 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 CHROME_RENDERER_EXTENSIONS_PLATFORM_APP_DISPATCHER_H_
+#define CHROME_RENDERER_EXTENSIONS_PLATFORM_APP_DISPATCHER_H_
+#pragma once
+
+#include "content/public/renderer/render_process_observer.h"
+
+// Dispatches platform-app control messages sent to the renderer.
+class PlatformAppDispatcher : public content::RenderProcessObserver {
+ public:
+  PlatformAppDispatcher();
+  ~PlatformAppDispatcher();
+
+ private:
+  virtual bool OnControlMessageReceived(const IPC::Message& message);
+  virtual void OnIsPlatformApp();
+
+  DISALLOW_COPY_AND_ASSIGN(PlatformAppDispatcher);
+};
+
+#endif  // CHROME_RENDERER_EXTENSIONS_PLATFORM_APP_DISPATCHER_H_