Chromecast: use CastContent{Browser,Renderer}Client as a base class.

chromecast/renderer/cast_content_renderer_client.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 CHROMECAST_RENDERER_CAST_CONTENT_RENDERER_CLIENT_H_
 #define CHROMECAST_RENDERER_CAST_CONTENT_RENDERER_CLIENT_H_
 
 #include <vector>
 
 #include "base/macros.h"
 #include "content/public/renderer/content_renderer_client.h"
 
 namespace IPC {
 class MessageFilter;
 }
 
 namespace network_hints {
 class PrescientNetworkingDispatcher;
 }  // namespace network_hints
 
 namespace chromecast {
 namespace shell {
 class CastRenderProcessObserver;
 
 // Adds any platform-specific bindings to the current frame.
 void PlatformAddRendererNativeBindings(blink::WebLocalFrame* frame);
 
 class CastContentRendererClient : public content::ContentRendererClient {
  public:
-  CastContentRendererClient();
+  // Creates an implementation of CastContentRendererClient. Platform should
+  // link in an implementation as needed.
+  static scoped_ptr<CastContentRendererClient> Create();
+
   ~CastContentRendererClient() override;
 
   // Returns any MessageFilters from the platform implementation that should
   // be added to the render process.
   std::vector<scoped_refptr<IPC::MessageFilter>>
   PlatformGetRendererMessageFilters();
 
   // ContentRendererClient implementation:
   void RenderThreadStarted() override;
   void RenderViewCreated(content::RenderView* render_view) override;
   void AddKeySystems(
       std::vector< ::media::KeySystemInfo>* key_systems) override;
 #if !defined(OS_ANDROID)
   scoped_ptr<::media::RendererFactory> CreateMediaRendererFactory(
       content::RenderFrame* render_frame,
       const scoped_refptr<::media::MediaLog>& media_log) override;
 #endif
   blink::WebPrescientNetworking* GetPrescientNetworking() override;
   void DeferMediaLoad(content::RenderFrame* render_frame,
                       const base::Closure& closure) override;
 
+ protected:
+  CastContentRendererClient();
+
  private:
   scoped_ptr<network_hints::PrescientNetworkingDispatcher>
       prescient_networking_dispatcher_;
   scoped_ptr<CastRenderProcessObserver> cast_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(CastContentRendererClient);
 };
 
 }  // namespace shell
 }  // namespace chromecast
 
 #endif  // CHROMECAST_RENDERER_CAST_CONTENT_RENDERER_CLIENT_H_