Add a 'remote' property to MediaSourceInterface. Also adding an implementation to the relevant sour…

talk/app/webrtc/rtpreceiver.cc

 /*
  * 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 67 matching lines @@
   if (!provider_) {
     return;
   }
   provider_->SetAudioPlayout(ssrc_, track_->enabled());
 }
 
 VideoRtpReceiver::VideoRtpReceiver(VideoTrackInterface* track,
                                    uint32_t ssrc,
                                    VideoProviderInterface* provider)
     : id_(track->id()), track_(track), ssrc_(ssrc), provider_(provider) {
+  RTC_DCHECK(track_->GetSource()->remote());
   provider_->SetVideoPlayout(ssrc_, true, track_->GetSource()->FrameInput());
 }
 
 VideoRtpReceiver::~VideoRtpReceiver() {
   // Since cricket::VideoRenderer is not reference counted,
   // we need to remove it from the provider before we are deleted.
   Stop();
 }
 
 void VideoRtpReceiver::Stop() {
   // TODO(deadbeef): Need to do more here to fully stop receiving packets.
   if (!provider_) {
     return;
   }
   provider_->SetVideoPlayout(ssrc_, false, nullptr);
   provider_ = nullptr;
 }
 
 }  // namespace webrtc