Introduce rtc::PacketTransportInterface and let cricket::TransportChannel inherit.

webrtc/p2p/base/dtlstransportchannel.cc

Index: webrtc/p2p/base/dtlstransportchannel.cc
diff --git a/webrtc/p2p/base/dtlstransportchannel.cc b/webrtc/p2p/base/dtlstransportchannel.cc
index d95bdcd916b1814ae4eda1eaeebd4f333e59f2ac..447c5f7c70171e1d1cd46e97c881255f15c168c4 100644
--- a/webrtc/p2p/base/dtlstransportchannel.cc
+++ b/webrtc/p2p/base/dtlstransportchannel.cc
@@ -14,6 +14,7 @@
 #include "webrtc/p2p/base/dtlstransportchannel.h"
 
 #include "webrtc/p2p/base/common.h"
+#include "webrtc/p2p/base/packettransportinterface.h"
 #include "webrtc/base/buffer.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/dscp.h"
@@ -437,9 +438,11 @@ bool DtlsTransportChannelWrapper::IsDtlsConnected() {
 //       start the DTLS handshake
 //     - Once the DTLS handshake completes, the state is that of the
 //       impl again
-void DtlsTransportChannelWrapper::OnWritableState(TransportChannel* channel) {
+void DtlsTransportChannelWrapper::OnWritableState(
+    rtc::PacketTransportInterface* transport) {
   ASSERT(rtc::Thread::Current() == worker_thread_);
-  ASSERT(channel == channel_);
+  RTC_DCHECK(transport ==
+             static_cast<rtc::PacketTransportInterface*>(channel_));
   LOG_J(LS_VERBOSE, this)
       << "DTLSTransportChannelWrapper: channel writable state changed to "
       << channel_->writable();
@@ -471,7 +474,7 @@ void DtlsTransportChannelWrapper::OnWritableState(TransportChannel* channel) {
 
 void DtlsTransportChannelWrapper::OnReceivingState(TransportChannel* channel) {
   ASSERT(rtc::Thread::Current() == worker_thread_);
-  ASSERT(channel == channel_);
+  RTC_DCHECK(channel == channel_);
   LOG_J(LS_VERBOSE, this)
       << "DTLSTransportChannelWrapper: channel receiving state changed to "
       << channel_->receiving();
@@ -482,10 +485,14 @@ void DtlsTransportChannelWrapper::OnReceivingState(TransportChannel* channel) {
 }
 
 void DtlsTransportChannelWrapper::OnReadPacket(
-    TransportChannel* channel, const char* data, size_t size,
-    const rtc::PacketTime& packet_time, int flags) {
+    rtc::PacketTransportInterface* transport,
+    const char* data,
+    size_t size,
+    const rtc::PacketTime& packet_time,
+    int flags) {
+  TransportChannel* channel = static_cast<TransportChannel*>(transport);
   ASSERT(rtc::Thread::Current() == worker_thread_);
-  ASSERT(channel == channel_);
+  RTC_DCHECK(channel == channel_);
   ASSERT(flags == 0);
 
   if (!dtls_active_) {
@@ -558,14 +565,15 @@ void DtlsTransportChannelWrapper::OnReadPacket(
 }
 
 void DtlsTransportChannelWrapper::OnSentPacket(
-    TransportChannel* channel,
+    rtc::PacketTransportInterface* transport,
     const rtc::SentPacket& sent_packet) {
   ASSERT(rtc::Thread::Current() == worker_thread_);
 
   SignalSentPacket(this, sent_packet);
 }
 
-void DtlsTransportChannelWrapper::OnReadyToSend(TransportChannel* channel) {
+void DtlsTransportChannelWrapper::OnReadyToSend(
+    rtc::PacketTransportInterface* transport) {
   if (writable()) {
     SignalReadyToSend(this);
   }