Media Remoting: Add interstitial elements to media element shadow dom.

third_party/WebKit/public/platform/WebMediaPlayerClient.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 98 matching lines @@
 
   // Warning: This method will destruct the caller.
   virtual void RequestReload(const WebURL& new_url) = 0;
 
   // Returns if there's a selected video track.
   virtual bool HasSelectedVideoTrack() = 0;
 
   // Returns the selected video track id (or an empty id if there's none).
   virtual WebMediaPlayer::TrackId GetSelectedVideoTrackId() = 0;
 
+  // Informs that media starts/stops being rendered and played back remotely.
+  virtual void MediaRemotingStarted() {}
+  virtual void MediaRemotingStopped() {}
+
  protected:
   ~WebMediaPlayerClient() {}
 };
 
 }  // namespace blink
 
 #endif