Wire-up BWE feedback for audio receive streams.

webrtc/audio_receive_stream.h

Index: webrtc/audio_receive_stream.h
diff --git a/webrtc/audio_receive_stream.h b/webrtc/audio_receive_stream.h
index daf45985d33c2523f85ee26891f4134643b66243..8cab094f4bed211946f878cbdbda25708aa75886 100644
--- a/webrtc/audio_receive_stream.h
+++ b/webrtc/audio_receive_stream.h
@@ -73,6 +73,12 @@ class AudioReceiveStream : public ReceiveStream {
       // Sender SSRC used for sending RTCP (such as receiver reports).
       uint32_t local_ssrc = 0;
 
+      // Enable feedback for send side bandwidth estimation.
+      // See
+      // https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions
+      // for details.
+      bool transport_cc = false;
+
       // RTP header extensions used for the received stream.
       std::vector<RtpExtension> extensions;
     } rtp;