Hookup the MediaStream glue for Adding and Removing tracks to an existing MediaStream.

content/renderer/media/media_stream_dependency_factory.h

Index: content/renderer/media/media_stream_dependency_factory.h
diff --git a/content/renderer/media/media_stream_dependency_factory.h b/content/renderer/media/media_stream_dependency_factory.h
index 27e4f4a5edcf5490e6e6accf966b7ad47b67bd32..d9c2bf9f7a19ac97f7307d50f78ba253ed4d8506 100644
--- a/content/renderer/media/media_stream_dependency_factory.h
+++ b/content/renderer/media/media_stream_dependency_factory.h
@@ -89,6 +89,10 @@ class CONTENT_EXPORT MediaStreamDependencyFactory
       WebKit::WebMediaStream* description,
       const MediaStreamExtraData::StreamStopCallback& stream_stop);
 
+  bool AddNativeLocalMediaTrack(
+      const WebKit::WebMediaStream& stream,
+      const WebKit::WebMediaStreamTrack& track);
+
   // Asks the libjingle PeerConnection factory to create a libjingle
   // PeerConnection object.
   // The PeerConnection object is owned by PeerConnectionHandler.