[Chromecast] Move audio logging from PushFrame to Start.

chromecast/media/audio/cast_audio_output_stream.cc

Index: chromecast/media/audio/cast_audio_output_stream.cc
diff --git a/chromecast/media/audio/cast_audio_output_stream.cc b/chromecast/media/audio/cast_audio_output_stream.cc
index 47b8dc313b13b8bf14e246b06af11183a2220e7c..d2de2085370d2c6a2eae249a68233418c19ed14e 100644
--- a/chromecast/media/audio/cast_audio_output_stream.cc
+++ b/chromecast/media/audio/cast_audio_output_stream.cc
@@ -152,6 +152,8 @@ void CastAudioOutputStream::Start(AudioSourceCallback* source_callback) {
   VLOG(1) << __FUNCTION__ << " : " << this;
   audio_worker_->Start(base::Bind(&CastAudioOutputStream::PushFrame,
                                   weak_factory_.GetWeakPtr(), source_callback));
+
+  metrics::CastMetricsHelper::GetInstance()->LogTimeToFirstAudio();
 }
 
 void CastAudioOutputStream::Stop() {
@@ -189,8 +191,6 @@ void CastAudioOutputStream::PushFrame(AudioSourceCallback* source_callback) {
     return;
   }
 
-  metrics::CastMetricsHelper::GetInstance()->LogTimeToFirstAudio();
-
   int frame_count = source_callback->OnMoreData(audio_bus_.get(), 0);
   DCHECK_EQ(frame_count, audio_bus_->frames());
   int buffer_size = frame_count * audio_params_.GetBytesPerFrame();