New accessor function VideoReceiveStream::Config::Rtp::AddRtxBinding

Needed temporarily, to enable landing of
https://codereview.webrtc.org/3000273002/ without breaking downstream
applications.

Bug: webrtc:7135
Change-Id: Ib0783d2e97cc62bb0a6e6fb394a29a5373938054
Reviewed-on: https://chromium-review.googlesource.com/631679
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Original-Commit-Position: refs/heads/master@{#19490}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 23bdb6773ed0e3f8ca2ab7722a4ffe7830527f95
diff --git a/call/video_receive_stream.h b/call/video_receive_stream.h
index 6e94382..bd4b997 100644
--- a/call/video_receive_stream.h
+++ b/call/video_receive_stream.h
@@ -171,7 +171,11 @@
       // Map from video payload type (apt) -> RTX payload type (pt).
       // For RTX to be enabled, both an SSRC and this mapping are needed.
       std::map<int, int> rtx_payload_types;
-
+      // TODO(nisse): This is a temporary accessor function to enable
+      // reversing and renaming of the rtx_payload_types mapping.
+      void AddRtxBinding(int rtx_payload_type, int media_payload_type) {
+        rtx_payload_types[media_payload_type] = rtx_payload_type;
+      }
       // RTP header extensions used for the received stream.
       std::vector<RtpExtension> extensions;
     } rtp;