add mediaType field to ssrc stat

talk/app/webrtc/statstypes.cc

Index: talk/app/webrtc/statstypes.cc
diff --git a/talk/app/webrtc/statstypes.cc b/talk/app/webrtc/statstypes.cc
index 19cb1f5d785c72b920e8c18b88da1afc9610e9dc..954f90f496beac92d55854c09eddbaf386edbd40 100644
--- a/talk/app/webrtc/statstypes.cc
+++ b/talk/app/webrtc/statstypes.cc
@@ -410,7 +410,8 @@ const char* StatsReport::Value::display_name() const {
       return "datachannelid";
     case kStatsValueNameCodecImplementationName:
       return "codecImplementationName";
-
+    case kStatsValueNameMediaType:
+      return "mediaType";
     // 'goog' prefixed constants.
     case kStatsValueNameAccelerateRate:
       return "googAccelerateRate";