Forward the number of skipped frames by the OS in audio playout.

media/audio/mac/audio_auhal_mac.h

Index: media/audio/mac/audio_auhal_mac.h
diff --git a/media/audio/mac/audio_auhal_mac.h b/media/audio/mac/audio_auhal_mac.h
index 0cd648a90253fada50c3d6ee073defdca8f3967a..aae8db9182b72ee3f586a36522b6f231d8b1ca66 100644
--- a/media/audio/mac/audio_auhal_mac.h
+++ b/media/audio/mac/audio_auhal_mac.h
@@ -126,7 +126,9 @@ class AUHALStream : public AudioOutputStream {
   // Gets the current playout latency value.
   double GetPlayoutLatency(const AudioTimeStamp* output_time_stamp);
 
-  void UpdatePlayoutTimestamp(const AudioTimeStamp* timestamp);
+  // Updates playout timestamp and total lost frames and glitches stats. Returns
+  // the number of lost frames (this render data request).
+  UInt32 UpdatePlayoutTimestampAndStats(const AudioTimeStamp* timestamp);
 
   // Called from the dtor and when the stream is reset.
   void ReportAndResetStats();