MediaRecorder: make MediaRecorderHandler a MediaStreamObserver

content/public/renderer/media_stream_api.cc

 // Copyright 2015 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/public/renderer/media_stream_api.h"
 
 #include "base/base64.h"
 #include "base/callback.h"
 #include "base/rand_util.h"
 #include "base/strings/utf_string_conversions.h"
+#include "content/renderer/media/media_stream.h"
 #include "content/renderer/media/media_stream_audio_source.h"
 #include "content/renderer/media/media_stream_video_capturer_source.h"
 #include "content/renderer/media/media_stream_video_track.h"
 #include "content/renderer/render_thread_impl.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebURL.h"
 #include "third_party/WebKit/public/web/WebMediaStreamRegistry.h"
 #include "url/gurl.h"
 
@@ skipping 101 matching lines @@
 
   blink::WebMediaStreamTrack web_media_audio_track;
   web_media_audio_track.initialize(webkit_source);
   RenderThreadImpl::current()->GetPeerConnectionDependencyFactory()->
       CreateLocalAudioTrack(web_media_audio_track);
 
   web_stream->addTrack(web_media_audio_track);
   return true;
 }
 
+CONTENT_EXPORT void AddMediaStreamTowebMediaStream(

[perkj_chrome, 2016/01/07 09:18:00]

? This seems wrong. In production , this happens when the MediaStream is
created. If the MediaStream is created by blink, this is triggered. 

https://code.google.com/p/chromium/codesearch#chromium/src/content/renderer/m...

[mcasas, 2016/01/08 00:14:12]

Yes, this is just for content_shell and is only invoked
in blink_test_runner.cc., see my comments elsewhere
as to the need for this method.

+    blink::WebMediaStream* web_stream) {
+  web_stream->setExtraData(new content::MediaStream());
+}
+
 }  // namespace content