Fix webkit_media::WebMediaPlayerProxy memory leak due to circular refcounting.

webkit/media/webmediaplayer_proxy.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 WEBKIT_MEDIA_WEBMEDIAPLAYER_PROXY_H_
 #define WEBKIT_MEDIA_WEBMEDIAPLAYER_PROXY_H_
 
 #include <list>
 
 #include "base/memory/ref_counted.h"
@@ skipping 85 matching lines @@
   // Notify |webmediaplayer_| that there's a network event.
   void NetworkEventTask(bool network_activity);
 
   // The render message loop where WebKit lives.
   MessageLoop* render_loop_;
   WebMediaPlayerImpl* webmediaplayer_;
 
   base::Lock data_sources_lock_;
   typedef std::list<scoped_refptr<WebDataSource> > DataSourceList;
   DataSourceList data_sources_;
-  WebDataSourceBuildObserverHack build_observer_;
 
   scoped_refptr<WebVideoRenderer> video_renderer_;
 
   base::Lock lock_;
   int outstanding_repaints_;
 
   scoped_refptr<media::ChunkDemuxer> chunk_demuxer_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(WebMediaPlayerProxy);
 };
 
 }  // namespace webkit_media
 
 #endif  // WEBKIT_MEDIA_WEBMEDIAPLAYER_PROXY_H_