Set audio format before adding pepper sink to audio track.

content/public/renderer/media_stream_audio_sink.cc

 // Copyright 2013 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_audio_sink.h"
 
 #include "base/logging.h"
 #include "content/renderer/media/media_stream_track.h"
 #include "content/renderer/media/webrtc_local_audio_track.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
@@ skipping 25 matching lines @@
   if (!native_track->is_local_track()) {
     LOG(ERROR) << "Can't remove the sink from a remote audio track";
     return;
   }
 
   WebRtcLocalAudioTrack* audio_track =
       static_cast<WebRtcLocalAudioTrack*>(native_track);
   audio_track->RemoveSink(sink);
 }
 
+media::AudioParameters MediaStreamAudioSink::GetFormatFromAudioTrack(
+    const blink::WebMediaStreamTrack& track) {
+  MediaStreamTrack* native_track = MediaStreamTrack::GetTrack(track);
+  if (!native_track->is_local_track()) {
+    LOG(ERROR) << "Can't get format from a remote audio track";
+    return media::AudioParameters();
+  }
+
+  WebRtcLocalAudioTrack* audio_track =
+      static_cast<WebRtcLocalAudioTrack*>(native_track);
+  return audio_track->GetOutputFormat();
+}
+
 }  // namespace content