Remove the dependency of TransportChannel and TransportChannelImpl.

webrtc/media/sctp/sctptransport.cc

Index: webrtc/media/sctp/sctptransport.cc
diff --git a/webrtc/media/sctp/sctptransport.cc b/webrtc/media/sctp/sctptransport.cc
index b95cf8a4baf444bc3f14aee79e47e9a9e2983d0a..f967c2aba7974a7bfcfd72cf34a8c09528d455cc 100644
--- a/webrtc/media/sctp/sctptransport.cc
+++ b/webrtc/media/sctp/sctptransport.cc
@@ -39,6 +39,7 @@ enum PreservedErrno {
 #include "webrtc/media/base/mediaconstants.h"
 #include "webrtc/media/base/rtputils.h"  // For IsRtpPacket
 #include "webrtc/media/base/streamparams.h"
+#include "webrtc/p2p/base/dtlstransportinternal.h"  // For PF_NORMAL
 
 namespace {
 
@@ -384,7 +385,7 @@ class SctpTransport::UsrSctpWrapper {
 };
 
 SctpTransport::SctpTransport(rtc::Thread* network_thread,
-                             TransportChannel* channel)
+                             rtc::PacketTransportInterface* channel)
     : network_thread_(network_thread),
       transport_channel_(channel),
       was_ever_writable_(channel->writable()) {
@@ -399,7 +400,8 @@ SctpTransport::~SctpTransport() {
   CloseSctpSocket();
 }
 
-void SctpTransport::SetTransportChannel(cricket::TransportChannel* channel) {
+void SctpTransport::SetTransportChannel(
+    rtc::PacketTransportInterface* channel) {
   RTC_DCHECK_RUN_ON(network_thread_);
   RTC_DCHECK(channel);
   DisconnectTransportChannelSignals();