Add comments about the Audio parts of the public Call API being WIP.

webrtc/audio_receive_stream.h

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_AUDIO_RECEIVE_STREAM_H_
 #define WEBRTC_AUDIO_RECEIVE_STREAM_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "webrtc/config.h"
 #include "webrtc/stream.h"
 #include "webrtc/transport.h"
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 class AudioDecoder;
 
+// WORK IN PROGRESS
+// This class is under development and is not yet intended for for use outside
+// of WebRtc/Libjingle. Please use the VoiceEngine API instead.
+// See: https://bugs.chromium.org/p/webrtc/issues/detail?id=4690
+
 class AudioReceiveStream : public ReceiveStream {
  public:
   struct Stats {
     uint32_t remote_ssrc = 0;
     int64_t bytes_rcvd = 0;
     uint32_t packets_rcvd = 0;
     uint32_t packets_lost = 0;
     float fraction_lost = 0.0f;
     std::string codec_name;
     uint32_t ext_seqnum = 0;
@@ skipping 55 matching lines @@
 
     // TODO(pbos): Remove config option once combined A/V BWE is always on.
     bool combined_audio_video_bwe = false;
   };
 
   virtual Stats GetStats() const = 0;
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_AUDIO_RECEIVE_STREAM_H_