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

webkit/media/webmediaplayer_proxy.cc

 // 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.
 
 #include "webkit/media/webmediaplayer_proxy.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "media/base/pipeline_status.h"
@@ skipping 32 matching lines @@
         NewRunnableMethod(this, &WebMediaPlayerProxy::RepaintTask));
   }
 }
 
 void WebMediaPlayerProxy::SetVideoRenderer(
     scoped_refptr<WebVideoRenderer> video_renderer) {
   video_renderer_ = video_renderer;
 }
 
 WebDataSourceBuildObserverHack WebMediaPlayerProxy::GetBuildObserver() {
-  if (build_observer_.is_null())
-    build_observer_ = base::Bind(&WebMediaPlayerProxy::AddDataSource, this);
-  return build_observer_;
+  return base::Bind(&WebMediaPlayerProxy::AddDataSource, this);
 }
 
 void WebMediaPlayerProxy::Paint(SkCanvas* canvas, const gfx::Rect& dest_rect) {
   DCHECK(MessageLoop::current() == render_loop_);
   if (video_renderer_) {
     video_renderer_->Paint(canvas, dest_rect);
   }
 }
 
 void WebMediaPlayerProxy::SetSize(const gfx::Rect& rect) {
@@ skipping 163 matching lines @@
   chunk_demuxer_ = demuxer;
   if (webmediaplayer_)
     webmediaplayer_->OnDemuxerOpened();
 }
 
 void WebMediaPlayerProxy::DemuxerClosedTask() {
   chunk_demuxer_ = NULL;
 }
 
 }  // namespace webkit_media