Adding a skeleton MediaStreamCenter.

content/renderer/media/media_stream_impl.h

Index: content/renderer/media/media_stream_impl.h
diff --git a/content/renderer/media/media_stream_impl.h b/content/renderer/media/media_stream_impl.h
index 503c510b12659c43c84580402d10476ea3f617fb..38182a6bf43e56ec8b3e2ffb4c8be8fbba3b977b 100644
--- a/content/renderer/media/media_stream_impl.h
+++ b/content/renderer/media/media_stream_impl.h
@@ -41,10 +41,16 @@ class Thread;
 }
 
 namespace WebKit {
+class WebMediaStreamCenter;
+class WebMediaStreamCenterClient;
 class WebPeerConnectionHandler;
 class WebPeerConnectionHandlerClient;
 }
 
+namespace content {
+class MediaStreamCenter;
+}
+
 class MediaStreamDispatcher;
 class MediaStreamDependencyFactory;
 class PeerConnectionHandler;
@@ -72,6 +78,8 @@ class CONTENT_EXPORT MediaStreamImpl
 
   virtual WebKit::WebPeerConnectionHandler* CreatePeerConnectionHandler(
       WebKit::WebPeerConnectionHandlerClient* client);
+  virtual WebKit::WebMediaStreamCenter* CreateMediaStreamCenter(
+      WebKit::WebMediaStreamCenterClient* client);
   virtual void ClosePeerConnection();
   virtual webrtc::MediaStreamTrackInterface* GetLocalMediaStreamTrack(
       const std::string& label);
@@ -158,6 +166,10 @@ class CONTENT_EXPORT MediaStreamImpl
   // TODO(grunell): Support several PeerConnectionsHandlers.
   PeerConnectionHandler* peer_connection_handler_;
 
+  // media_stream_center_ is a raw pointer, owned by WebKit. It's valid for
+  // the lifetime of RenderView.
+  content::MediaStreamCenter* media_stream_center_;
+
   // We keep a list of the generated local tracks, so that we can add capture
   // devices when generated and also use them for recording.
   typedef talk_base::scoped_refptr<webrtc::MediaStreamTrackInterface>