Build WebRTC with data channel only.

webrtc/pc/channel.cc

 /*
  *  Copyright 2004 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.
  */
 
@@ skipping 1589 matching lines @@
                                              webrtc::RtpParameters parameters) {
   return media_channel()->SetRtpReceiveParameters(ssrc, parameters);
 }
 
 bool VoiceChannel::GetStats(VoiceMediaInfo* stats) {
   return InvokeOnWorker(RTC_FROM_HERE, Bind(&VoiceMediaChannel::GetStats,
                                             media_channel(), stats));
 }
 
 std::vector<webrtc::RtpSource> VoiceChannel::GetSources(uint32_t ssrc) const {
+#if defined(HAVE_WEBRTC_VOICE) && defined(HAVE_WEBRTC_VIDEO)

[Taylor Brandstetter, 2017/05/11 04:43:11]

Only need HAVE_WEBRTC_VOICE, technically.

[Zhi Huang, 2017/05/12 20:05:33]

Done.

   return worker_thread()->Invoke<std::vector<webrtc::RtpSource>>(
       RTC_FROM_HERE,
       Bind(&WebRtcVoiceMediaChannel::GetSources,
            static_cast<WebRtcVoiceMediaChannel*>(media_channel()), ssrc));
+#else
+  return std::vector<webrtc::RtpSource>();
+#endif
 }
 
 void VoiceChannel::StartMediaMonitor(int cms) {
   media_monitor_.reset(new VoiceMediaMonitor(media_channel(), worker_thread(),
       rtc::Thread::Current()));
   media_monitor_->SignalUpdate.connect(
       this, &VoiceChannel::OnMediaMonitorUpdate);
   media_monitor_->Start(cms);
 }
 
@@ skipping 776 matching lines @@
 
 void RtpDataChannel::OnDataChannelReadyToSend(bool writable) {
   // This is usded for congestion control to indicate that the stream is ready
   // to send by the MediaChannel, as opposed to OnReadyToSend, which indicates
   // that the transport channel is ready.
   signaling_thread()->Post(RTC_FROM_HERE, this, MSG_READYTOSENDDATA,
                            new DataChannelReadyToSendMessageData(writable));
 }
 
 }  // namespace cricket