Revert of Remove references between RTCPeerConnection and RTCDataChannel.

third_party/WebKit/Source/modules/mediastream/RTCPeerConnection.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * 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
@@ skipping 181 matching lines @@
 
     void closeInternal();
 
     SignalingState m_signalingState;
     ICEGatheringState m_iceGatheringState;
     ICEConnectionState m_iceConnectionState;
 
     MediaStreamVector m_localStreams;
     MediaStreamVector m_remoteStreams;
 
+    HeapVector<Member<RTCDataChannel>> m_dataChannels;
+
     OwnPtr<WebRTCPeerConnectionHandler> m_peerHandler;
 
     Member<AsyncMethodRunner<RTCPeerConnection>> m_dispatchScheduledEventRunner;
     HeapVector<Member<EventWrapper>> m_scheduledEvents;
 
     bool m_stopped;
     bool m_closed;
 };
 
 } // namespace blink
 
 #endif // RTCPeerConnection_h