Expose codec implementation names in stats.

talk/media/base/mediachannel.h

Index: talk/media/base/mediachannel.h
diff --git a/talk/media/base/mediachannel.h b/talk/media/base/mediachannel.h
index 0a59019256e5541295f52bc5e8ec35225d725272..f6fb77d8a6db018a886b0268920c175623a4b82c 100644
--- a/talk/media/base/mediachannel.h
+++ b/talk/media/base/mediachannel.h
@@ -783,6 +783,7 @@ struct VideoSenderInfo : public MediaSenderInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string encoder_implementation_name;
   int packets_cached;
   int firs_rcvd;
   int plis_rcvd;
@@ -828,6 +829,7 @@ struct VideoReceiverInfo : public MediaReceiverInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string decoder_implementation_name;
   int packets_concealed;
   int firs_sent;
   int plis_sent;