Add AEC filter divergence metric to StatsCollector.

webrtc/api/statstypes.cc

Index: webrtc/api/statstypes.cc
diff --git a/webrtc/api/statstypes.cc b/webrtc/api/statstypes.cc
index feeead43745b19ae7b2245b5576faa8aa409d18e..e4f8b1738afb94a57d92888e7b3eed542a4fb463 100644
--- a/webrtc/api/statstypes.cc
+++ b/webrtc/api/statstypes.cc
@@ -371,6 +371,8 @@ const char* StatsReport::Value::display_name() const {
       return "bytesSent";
     case kStatsValueNamePacketsSent:
       return "packetsSent";
+    case kStatsValueNameAecDivergentFilterFraction:

[tommi, 2016/04/07 13:37:02]

looks like we've regressed from the alphabetic order here, but if you could fix
it here so that Aec comes before Audio, that would be good.

[minyue-webrtc, 2016/04/07 14:29:40]

Done.

+      return "aecDivergentFilterFraction";
     case kStatsValueNameBytesReceived:
       return "bytesReceived";
     case kStatsValueNameLabel: