Set audio format before adding pepper sink to audio track.

content/renderer/pepper/pepper_media_stream_audio_track_host.cc

Index: content/renderer/pepper/pepper_media_stream_audio_track_host.cc
diff --git a/content/renderer/pepper/pepper_media_stream_audio_track_host.cc b/content/renderer/pepper/pepper_media_stream_audio_track_host.cc
index c2dacf535cac5df0f916c027e1e66db3458edd59..c8f9e7d51509be2690f9c76caf8558cb2e8a1bd5 100644
--- a/content/renderer/pepper/pepper_media_stream_audio_track_host.cc
+++ b/content/renderer/pepper/pepper_media_stream_audio_track_host.cc
@@ -364,6 +364,13 @@ void PepperMediaStreamAudioTrackHost::OnNewBufferEnqueued() {
 
 void PepperMediaStreamAudioTrackHost::DidConnectPendingHostToResource() {
   if (!connected_) {
+    media::AudioParameters format =
+        MediaStreamAudioSink::GetFormatFromAudioTrack(track_);
+    // Although this should only be called on the audio capture thread, that
+    // can't happen until the sink is added to the audio track below.
+    if (format.IsValid())
+      audio_sink_.OnSetFormat(format);
+
     MediaStreamAudioSink::AddToAudioTrack(&audio_sink_, track_);
     connected_ = true;
   }