Build WebRTC with data channel only.

webrtc/pc/peerconnectionfactory.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 38 matching lines @@
   // safely call Initialize directly.
   if (!pc_factory->Initialize()) {
     return nullptr;
   }
   return PeerConnectionFactoryProxy::Create(pc_factory->signaling_thread(),
                                             pc_factory);
 }
 
 rtc::scoped_refptr<PeerConnectionFactoryInterface>
 CreatePeerConnectionFactory() {
-  return CreatePeerConnectionFactory(CreateBuiltinAudioEncoderFactory(),
-                                     CreateBuiltinAudioDecoderFactory());
+  rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory;
+  rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory;
+#ifdef HAVE_MEDIA
+  audio_encoder_factory = CreateBuiltinAudioEncoderFactory();
+  audio_decoder_factory = CreateBuiltinAudioDecoderFactory();
+#endif
+  return CreatePeerConnectionFactory(audio_encoder_factory,
+                                     audio_decoder_factory);
 }
 
 rtc::scoped_refptr<PeerConnectionFactoryInterface> CreatePeerConnectionFactory(
     rtc::Thread* network_thread,
     rtc::Thread* worker_thread,
     rtc::Thread* signaling_thread,
     AudioDeviceModule* default_adm,
     rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory,
     rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory,
     cricket::WebRtcVideoEncoderFactory* video_encoder_factory,
@@ skipping 47 matching lines @@
 
 rtc::scoped_refptr<PeerConnectionFactoryInterface>
 CreatePeerConnectionFactoryWithAudioMixer(
     rtc::Thread* network_thread,
     rtc::Thread* worker_thread,
     rtc::Thread* signaling_thread,
     AudioDeviceModule* default_adm,
     cricket::WebRtcVideoEncoderFactory* encoder_factory,
     cricket::WebRtcVideoDecoderFactory* decoder_factory,
     rtc::scoped_refptr<AudioMixer> audio_mixer) {
+  rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory;
+  rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory;
+#ifdef HAVE_MEDIA
+  audio_encoder_factory = CreateBuiltinAudioEncoderFactory();
+  audio_decoder_factory = CreateBuiltinAudioDecoderFactory();
+#endif
   return CreatePeerConnectionFactoryWithAudioMixer(
       network_thread, worker_thread, signaling_thread, default_adm,
-      CreateBuiltinAudioEncoderFactory(), CreateBuiltinAudioDecoderFactory(),
-      encoder_factory, decoder_factory, audio_mixer);
+      audio_encoder_factory, audio_decoder_factory, encoder_factory,
+      decoder_factory, audio_mixer);
 }
 
 PeerConnectionFactory::PeerConnectionFactory(
     rtc::scoped_refptr<webrtc::AudioEncoderFactory> audio_encoder_factory,
     rtc::scoped_refptr<webrtc::AudioDecoderFactory> audio_decoder_factory)
     : owns_ptrs_(true),
       wraps_current_thread_(false),
       network_thread_(rtc::Thread::CreateWithSocketServer().release()),
       worker_thread_(rtc::Thread::Create().release()),
       signaling_thread_(rtc::Thread::Current()),
@@ skipping 240 matching lines @@
   return worker_thread_;
 }
 
 rtc::Thread* PeerConnectionFactory::network_thread() {
   return network_thread_;
 }
 
 std::unique_ptr<cricket::MediaEngineInterface>
 PeerConnectionFactory::CreateMediaEngine_w() {
   RTC_DCHECK(worker_thread_ == rtc::Thread::Current());
+#ifdef HAVE_MEDIA
   return std::unique_ptr<cricket::MediaEngineInterface>(
       cricket::WebRtcMediaEngineFactory::Create(
-          default_adm_.get(), audio_encoder_factory_,
-          audio_decoder_factory_,
+          default_adm_.get(), audio_encoder_factory_, audio_decoder_factory_,
           video_encoder_factory_.get(), video_decoder_factory_.get(),
           external_audio_mixer_));
+#else
+  return std::unique_ptr<cricket::MediaEngineInterface>();
+#endif

[pthatcher1, 2017/05/03 18:05:53]

Why not just not call CreateMediaEngine_w from
PeerConnectionFactory::Initialize()?

[Zhi Huang, 2017/05/04 01:08:03]

The idea here is trying to avoid compiling and linking the method
WebRtcMediaFactory::Create(). It seems that not calling it from Initialize()
doesn't help.

[pthatcher1, 2017/05/05 01:45:12]

Ah, duh.  You're right.

 }
 
 }  // namespace webrtc