Build WebRTC with data channel only.

webrtc/api/peerconnectioninterface.h

Index: webrtc/api/peerconnectioninterface.h
diff --git a/webrtc/api/peerconnectioninterface.h b/webrtc/api/peerconnectioninterface.h
index 8ff7e1e469c7805e84eed4a0ec2eadb1c5874a23..5ce832e14298c11ea3d436e39aab0f923b7dae81 100644
--- a/webrtc/api/peerconnectioninterface.h
+++ b/webrtc/api/peerconnectioninterface.h
@@ -90,6 +90,8 @@
 #include "webrtc/base/rtccertificategenerator.h"
 #include "webrtc/base/socketaddress.h"
 #include "webrtc/base/sslstreamadapter.h"
+#include "webrtc/call/callfactoryinterface.h"
+#include "webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h"
 #include "webrtc/media/base/mediachannel.h"
 #include "webrtc/media/base/videocapturer.h"
 #include "webrtc/p2p/base/portallocator.h"
@@ -100,6 +102,7 @@ class Thread;
 }
 
 namespace cricket {
+class MediaEngineInterface;
 class WebRtcVideoDecoderFactory;
 class WebRtcVideoEncoderFactory;
 }
@@ -107,6 +110,7 @@ class WebRtcVideoEncoderFactory;
 namespace webrtc {
 class AudioDeviceModule;
 class AudioMixer;
+class CallFactoryInterface;
 class MediaConstraintsInterface;
 
 // MediaStream container interface.
@@ -1126,6 +1130,21 @@ CreatePeerConnectionFactory(
       default_adm, encoder_factory, decoder_factory);
 }
 
+rtc::scoped_refptr<PeerConnectionFactoryInterface>
+CreateModularPeerConnectionFactory(
+    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,
+    cricket::WebRtcVideoDecoderFactory* video_decoder_factory,
+    rtc::scoped_refptr<AudioMixer> audio_mixer,
+    std::unique_ptr<cricket::MediaEngineInterface> media_engine,
+    std::unique_ptr<CallFactoryInterface> call_factory,
+    std::unique_ptr<RtcEventLogFactoryInterface> event_log_factory);
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_PEERCONNECTIONINTERFACE_H_