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 05d56cf9e06a1a58ddc38424882fab9b3202dfb5..d651dadf6b14482a7e0e35ae9986c3aee628ac3d 100644
--- a/talk/media/base/mediachannel.h
+++ b/talk/media/base/mediachannel.h
@@ -832,6 +832,7 @@ struct VideoSenderInfo : public MediaSenderInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string encoder_implementation_name;
   int packets_cached;
   int firs_rcvd;
   int plis_rcvd;
@@ -877,6 +878,7 @@ struct VideoReceiverInfo : public MediaReceiverInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string decoder_implementation_name;
   int packets_concealed;
   int firs_sent;
   int plis_sent;