Use RtxReceiveStream.

webrtc/config.h

Index: webrtc/config.h
diff --git a/webrtc/config.h b/webrtc/config.h
index 962e0f2fb9ac844ff243c0425c1b9df4dca76a4d..c1c2d926eda50c710fdc45dfd69ca52f6baff3af 100644
--- a/webrtc/config.h
+++ b/webrtc/config.h
@@ -49,6 +49,15 @@ struct UlpfecConfig {
   // Payload type used for ULPFEC packets.
   int ulpfec_payload_type;
 
+  // TODO(nisse): Unclear to me if the next two values belong here?

[danilchap, 2017/08/29 13:33:06]

why this comment belong to the CL?
why this description is a TODO? May be instead of the question leave description
how flags are used/supposed to be used.

[nisse-webrtc, 2017/08/29 13:51:36]

I can try to rephrase or move. Comment is here because it makes the flags unused
on one important code path.

Current plan was outlined in a comment on gerrit: Leave as is here, but in
VideoReceiveStreamConfig, replace structUlpfecConfig with just an int
ulpfec_payload_type. I can write that as a TODO at that place instead.

[nisse-webrtc, 2017/08/30 11:49:05]

Done.

+  // Currently, red_rtx_payload_type is used mainly only on the send
+  // side. On the receive side, configuration of the per-packet
+  // processing is done via
+  // VideoReceiveStream::Config::Rtp::rtx_payload_types, but that
+  // mapping is populated by
+  // WebRtcVideoChannel::WebRtcVideoReceiveStream in
+  // webrtcvideoengine.cc based on the values in this struct.
+
   // Payload type used for RED packets.
   int red_payload_type;