Fix for data channels perpetually stuck in "closing" state.

webrtc/api/datachannel.h

Index: webrtc/api/datachannel.h
diff --git a/webrtc/api/datachannel.h b/webrtc/api/datachannel.h
index 3fb400b7ec4cf8ae89c29f91b9095c68b8c7275e..714e6e397e4448d1899666842116a970a84af122 100644
--- a/webrtc/api/datachannel.h
+++ b/webrtc/api/datachannel.h
@@ -158,6 +158,8 @@ class DataChannel : public DataChannelInterface,
   // Only needs to be called for SCTP data channels.
   void OnTransportChannelCreated();
   // Called when the transport channel is destroyed.
+  // This method makes sure the DataChannel is disconnected and changes state
+  // to kClosed.
   void OnTransportChannelDestroyed();
 
   // The following methods are for RTP only.