Add decoder-specific settings with proper lifetime.

webrtc/video/video_receive_stream.cc

Index: webrtc/video/video_receive_stream.cc
diff --git a/webrtc/video/video_receive_stream.cc b/webrtc/video/video_receive_stream.cc
index bc51269b85916e1daf085f17b96a6cfb4bb59734..409e8460f7f587f03e2aed6ca8336893b5ad51ec 100644
--- a/webrtc/video/video_receive_stream.cc
+++ b/webrtc/video/video_receive_stream.cc
@@ -47,6 +47,11 @@ std::string VideoReceiveStream::Decoder::ToString() const {
   ss << "{decoder: " << (decoder ? "(VideoDecoder)" : "nullptr");
   ss << ", payload_type: " << payload_type;
   ss << ", payload_name: " << payload_name;
+  ss << ", decoder_specific: {";
+  ss << " h264_extra_settings: "
+     << (decoder_specific.h264_extra_settings ? "(h264_extra_settings)"
+                                              : "nullptr");
+  ss << '}';
   ss << '}';
 
   return ss.str();