Add support for data channels with Unified Plan

Bug: webrtc:7600
Change-Id: Idca1219fa692b24ced104aff7e89cde8a1bfe301
Reviewed-on: https://webrtc-review.googlesource.com/36240
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Peter Thatcher <pthatcher@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21478}
diff --git a/pc/peerconnectionwrapper.cc b/pc/peerconnectionwrapper.cc
index d297054..5d804a8 100644
--- a/pc/peerconnectionwrapper.cc
+++ b/pc/peerconnectionwrapper.cc
@@ -278,6 +278,11 @@
   return pc()->AddTrack(CreateVideoTrack(track_label), std::move(streams));
 }
 
+rtc::scoped_refptr<DataChannelInterface>
+PeerConnectionWrapper::CreateDataChannel(const std::string& label) {
+  return pc()->CreateDataChannel(label, nullptr);
+}
+
 PeerConnectionInterface::SignalingState
 PeerConnectionWrapper::signaling_state() {
   return pc()->signaling_state();