Make SCTPtransport enter "closed" state when DTLStransport does.

Bug: webrtc:11090
Change-Id: I30e0b70387746d6c544ed1818f276569d4258cf4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/159888
Reviewed-by: Emad Omara <emadomara@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29810}
diff --git a/pc/data_channel.h b/pc/data_channel.h
index 728226c..c7dc6ea 100644
--- a/pc/data_channel.h
+++ b/pc/data_channel.h
@@ -185,10 +185,10 @@
   // Called when the transport channel is created.
   // Only needs to be called for SCTP data channels.
   void OnTransportChannelCreated();
-  // Called when the transport channel is destroyed.
+  // Called when the transport channel is unusable.
   // This method makes sure the DataChannel is disconnected and changes state
   // to kClosed.
-  void OnTransportChannelDestroyed();
+  void OnTransportChannelClosed();
 
   /*******************************************
    * The following methods are for RTP only. *