Support for remote audio into tracks

talk/app/webrtc/rtpreceiver.h

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 50 matching lines @@
     return track_.get();
   }
 
   std::string id() const override { return id_; }
 
   void Stop() override;
 
  private:
   void Reconfigure();
 
-  std::string id_;
-  rtc::scoped_refptr<AudioTrackInterface> track_;
-  uint32_t ssrc_;
-  AudioProviderInterface* provider_;
+  const std::string id_;
+  const rtc::scoped_refptr<AudioTrackInterface> track_;
+  const uint32_t ssrc_;
+  AudioProviderInterface* provider_;  // Set to null in Stop().
   bool cached_track_enabled_;
 };
 
 class VideoRtpReceiver : public rtc::RefCountedObject<RtpReceiverInterface> {
  public:
   VideoRtpReceiver(VideoTrackInterface* track,
                    uint32_t ssrc,
                    VideoProviderInterface* provider);
 
   virtual ~VideoRtpReceiver();
@@ skipping 10 matching lines @@
  private:
   std::string id_;
   rtc::scoped_refptr<VideoTrackInterface> track_;
   uint32_t ssrc_;
   VideoProviderInterface* provider_;
 };
 
 }  // namespace webrtc
 
 #endif  // TALK_APP_WEBRTC_RTPRECEIVER_H_