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 3f777b3bbcb560a69625bd009a812e3149ef7cab..f6b302fec4ac1e850fce4b8419901dbd93d9d6b7 100644
--- a/talk/media/base/mediachannel.h
+++ b/talk/media/base/mediachannel.h
@@ -786,6 +786,7 @@ struct VideoSenderInfo : public MediaSenderInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string encoder_implementation_name;
   int packets_cached;
   int firs_rcvd;
   int plis_rcvd;
@@ -831,6 +832,7 @@ struct VideoReceiverInfo : public MediaReceiverInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string decoder_implementation_name;
   int packets_concealed;
   int firs_sent;
   int plis_sent;