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 14660847fa2114b0138a4cfcdf33440d58f86f26..3dbd467e3aaae2fea3131e61792f9a0f519c0495 100644
--- a/talk/media/base/mediachannel.h
+++ b/talk/media/base/mediachannel.h
@@ -820,6 +820,7 @@ struct VideoSenderInfo : public MediaSenderInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string encoder_implementation_name;
   int packets_cached;
   int firs_rcvd;
   int plis_rcvd;
@@ -865,6 +866,7 @@ struct VideoReceiverInfo : public MediaReceiverInfo {
   }
 
   std::vector<SsrcGroup> ssrc_groups;
+  std::string decoder_implementation_name;
   int packets_concealed;
   int firs_sent;
   int plis_sent;