Revert of make the DtlsTransportWrapper inherit form DtlsTransportInternal

webrtc/media/sctp/sctptransportinternal.h

Index: webrtc/media/sctp/sctptransportinternal.h
diff --git a/webrtc/media/sctp/sctptransportinternal.h b/webrtc/media/sctp/sctptransportinternal.h
index 8492713ecdd60d10890ba5e44df9d156c5621f24..7dd6bc7ea7a8f93b7c77c16b08f9b8cc2ccfc5af 100644
--- a/webrtc/media/sctp/sctptransportinternal.h
+++ b/webrtc/media/sctp/sctptransportinternal.h
@@ -24,7 +24,7 @@
 // TODO(deadbeef): Use something else for SCTP. It's confusing that we use an
 // SSRC field for SID.
 #include "webrtc/media/base/mediachannel.h"
-#include "webrtc/p2p/base/packettransportinterface.h"
+#include "webrtc/p2p/base/transportchannel.h"
 
 namespace cricket {
 
@@ -58,7 +58,7 @@
   // Changes what underlying DTLS channel is uses. Used when switching which
   // bundled transport the SctpTransport uses.
   // Assumes |channel| is non-null.
-  virtual void SetTransportChannel(rtc::PacketTransportInterface* channel) = 0;
+  virtual void SetTransportChannel(TransportChannel* channel) = 0;
 
   // When Start is called, connects as soon as possible; this can be called
   // before DTLS completes, in which case the connection will begin when DTLS
@@ -129,7 +129,7 @@
 
   // Create an SCTP transport using |channel| for the underlying transport.
   virtual std::unique_ptr<SctpTransportInternal> CreateSctpTransport(
-      rtc::PacketTransportInterface* channel) = 0;
+      TransportChannel* channel) = 0;
 };
 
 }  // namespace cricket