Update MediaStreamTrack::Stop to latest draft.

content/renderer/media/media_stream_track.cc

 // Copyright 2014 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 "content/renderer/media/media_stream_track.h"
 
 #include "base/logging.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/libjingle/source/talk/app/webrtc/mediastreaminterface.h"
 
@@ skipping 13 matching lines @@
 }
 
 MediaStreamTrack::~MediaStreamTrack() {
 }
 
 void MediaStreamTrack::SetEnabled(bool enabled) {
   if (track_)
     track_->set_enabled(enabled);
 }
 
+void MediaStreamTrack::StopTrack() {
+  // StopTrack means that a track should be stopped permanently. But
+  // since there is no proper way of doing that on a remote track, we can
+  // at least disable the track. Blink will not call down to the content layer
+  // after a track has been stopped.
+  if (track_)
+    track_->set_enabled(false);
+}
+
 webrtc::AudioTrackInterface* MediaStreamTrack::GetAudioAdapter() {
   return static_cast<webrtc::AudioTrackInterface*>(track_.get());
 }
 
 webrtc::VideoTrackInterface* MediaStreamTrack::GetVideoAdapter() {
   NOTREACHED();
   return NULL;
 }
 
 }  // namespace content