Set audio format before adding pepper sink to audio track.

content/public/renderer/media_stream_audio_sink.cc

Index: content/public/renderer/media_stream_audio_sink.cc
diff --git a/content/public/renderer/media_stream_audio_sink.cc b/content/public/renderer/media_stream_audio_sink.cc
index 5b14f95b4f254c09a5b98c95811fc7f8695ddb52..01b67891d91752a1160197637496ec197bebc16d 100644
--- a/content/public/renderer/media_stream_audio_sink.cc
+++ b/content/public/renderer/media_stream_audio_sink.cc
@@ -43,4 +43,20 @@ void MediaStreamAudioSink::RemoveFromAudioTrack(
   audio_track->RemoveSink(sink);
 }
 
+const media::AudioParameters& MediaStreamAudioSink::GetFormatFromAudioTrack(
+    const blink::WebMediaStreamTrack& track) {
+  // Invalid AudioParameters to return when track is remote. Needed because we
+  // return a reference.

[dmichael (off chromium), 2015/01/20 17:07:03]

I think it would be a lot better to just return by-value.

[Anand Mistry (off Chromium), 2015/01/27 02:12:10]

Done.

+  static const media::AudioParameters null_format;

[DaleCurtis, 2015/01/20 18:46:56]

This seems unnecessary, just return media::AudioParameters() below. Is there a
reason you are static const'ing for speed? :)

[Anand Mistry (off Chromium), 2015/01/27 02:12:10]

Because it needs to survive after the function call sicne it's returned by
reference. Removed since I'm now returning by value.

+  MediaStreamTrack* native_track = MediaStreamTrack::GetTrack(track);
+  if (!native_track->is_local_track()) {
+    LOG(ERROR) << "Can't get format from a remote audio track";
+    return null_format;
+  }
+
+  WebRtcLocalAudioTrack* audio_track =
+      static_cast<WebRtcLocalAudioTrack*>(native_track);
+  return audio_track->GetOutputFormat();
+}
+
 }  // namespace content