Add support for unmixed audio from remote WebRTC remote tracks.

content/renderer/media/webrtc/webrtc_media_stream_adapter.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/webrtc/webrtc_media_stream_adapter.h"
 
 #include "base/logging.h"
 #include "content/renderer/media/media_stream_audio_source.h"
+#include "content/renderer/media/media_stream_audio_track.h"
 #include "content/renderer/media/media_stream_track.h"
 #include "content/renderer/media/webrtc/media_stream_video_webrtc_sink.h"
 #include "content/renderer/media/webrtc/peer_connection_dependency_factory.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 
 namespace content {
 
 WebRtcMediaStreamAdapter::WebRtcMediaStreamAdapter(
@@ skipping 51 matching lines @@
       }
     }
   }
 }
 
 void WebRtcMediaStreamAdapter::CreateAudioTrack(
     const blink::WebMediaStreamTrack& track) {
   DCHECK_EQ(track.source().type(), blink::WebMediaStreamSource::TypeAudio);
   // A media stream is connected to a peer connection, enable the
   // peer connection mode for the sources.
-  MediaStreamTrack* native_track = MediaStreamTrack::GetTrack(track);
+  MediaStreamAudioTrack* native_track = MediaStreamAudioTrack::GetTrack(track);
   if (!native_track || !native_track->is_local_track()) {
     // We don't support connecting remote audio tracks to PeerConnection yet.
     // See issue http://crbug/344303.
     // TODO(xians): Remove this after we support connecting remote audio track
     // to PeerConnection.
     NOTIMPLEMENTED() << "webrtc audio track can not be created from a remote "
                      << "audio track.";
     return;
   }
 
@@ skipping 10 matching lines @@
 void WebRtcMediaStreamAdapter::CreateVideoTrack(
     const blink::WebMediaStreamTrack& track) {
   DCHECK_EQ(track.source().type(), blink::WebMediaStreamSource::TypeVideo);
   MediaStreamVideoWebRtcSink* adapter =
       new MediaStreamVideoWebRtcSink(track, factory_);
   video_adapters_.push_back(adapter);
   webrtc_media_stream_->AddTrack(adapter->webrtc_video_track());
 }
 
 }  // namespace content