Add histogram stats for AV sync stream offset:

webrtc/video/receive_statistics_proxy.cc

Index: webrtc/video/receive_statistics_proxy.cc
diff --git a/webrtc/video/receive_statistics_proxy.cc b/webrtc/video/receive_statistics_proxy.cc
index abf297f56f962b3af150f673cc7d50ba3c9ebab2..6f795f18efa3cb8bf4c7216184d5ef1da4a8aada 100644
--- a/webrtc/video/receive_statistics_proxy.cc
+++ b/webrtc/video/receive_statistics_proxy.cc
@@ -59,6 +59,10 @@ void ReceiveStatisticsProxy::UpdateHistograms() {
     RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.ReceivedWidthInPixels", width);
     RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.ReceivedHeightInPixels", height);
   }
+  int sync_offset_ms = render_sync_offset_counter_.Avg(kMinRequiredSamples);
+  if (sync_offset_ms != -1)
+    RTC_HISTOGRAM_COUNTS_10000("WebRTC.Video.AVSyncOffsetInMs", sync_offset_ms);
+
   int qp = qp_counters_.vp8.Avg(kMinRequiredSamples);
   if (qp != -1)
     RTC_HISTOGRAM_COUNTS_200("WebRTC.Video.Decoded.Vp8.Qp", qp);
@@ -220,7 +224,9 @@ void ReceiveStatisticsProxy::OnDecodedFrame() {
   stats_.decode_frame_rate = decode_fps_estimator_.Rate(now);
 }
 
-void ReceiveStatisticsProxy::OnRenderedFrame(int width, int height) {
+void ReceiveStatisticsProxy::OnRenderedFrame(int width,
+                                             int height,
+                                             int64_t stream_sync_offset_ms) {
   RTC_DCHECK_GT(width, 0);
   RTC_DCHECK_GT(height, 0);
   uint64_t now = clock_->TimeInMilliseconds();
@@ -232,6 +238,9 @@ void ReceiveStatisticsProxy::OnRenderedFrame(int width, int height) {
   render_height_counter_.Add(height);
   render_fps_tracker_.AddSamples(1);
   render_pixel_tracker_.AddSamples(sqrt(width * height));
+
+  if (stream_sync_offset_ms != -1)
+    render_sync_offset_counter_.Add(stream_sync_offset_ms);

[pbos-webrtc, 2016/03/04 14:34:27]

Should we expose this in getStats as well?

[åsapersson, 2016/03/09 15:44:35]

Done.

 }
 
 void ReceiveStatisticsProxy::OnReceiveRatesUpdated(uint32_t bitRate,