Move responsibility for RTP header extensions on video receive.

call/flexfec_receive_stream_impl.cc

Index: call/flexfec_receive_stream_impl.cc
diff --git a/call/flexfec_receive_stream_impl.cc b/call/flexfec_receive_stream_impl.cc
index bb68f6e6e82d0d9de52841de0de29315d276a673..55ac7f32b1edf19f0b698b2a3f56b14cc6071c90 100644
--- a/call/flexfec_receive_stream_impl.cc
+++ b/call/flexfec_receive_stream_impl.cc
@@ -44,13 +44,7 @@ std::string FlexfecReceiveStream::Config::ToString() const {
   if (!protected_media_ssrcs.empty())
     ss << protected_media_ssrcs[i];
   ss << "], transport_cc: " << (transport_cc ? "on" : "off");
-  ss << ", rtp_header_extensions: [";
-  i = 0;
-  for (; i + 1 < rtp_header_extensions.size(); ++i)
-    ss << rtp_header_extensions[i].ToString() << ", ";
-  if (!rtp_header_extensions.empty())
-    ss << rtp_header_extensions[i].ToString();
-  ss << "]}";
+  ss << "}";
   return ss.str();
 }