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

webrtc/p2p/base/dtlstransportchannel_unittest.cc

Index: webrtc/p2p/base/dtlstransportchannel_unittest.cc
diff --git a/webrtc/p2p/base/dtlstransportchannel_unittest.cc b/webrtc/p2p/base/dtlstransportchannel_unittest.cc
index 0a6e254e8fa726a739d7c60998a9a625e9c6459f..9b65f896142c681a9e2b4d8438dac00f1cff4412 100644
--- a/webrtc/p2p/base/dtlstransportchannel_unittest.cc
+++ b/webrtc/p2p/base/dtlstransportchannel_unittest.cc
@@ -13,6 +13,7 @@
 
 #include "webrtc/p2p/base/dtlstransport.h"
 #include "webrtc/p2p/base/faketransportcontroller.h"
+#include "webrtc/p2p/base/packettransport.h"
 #include "webrtc/base/common.h"
 #include "webrtc/base/dscp.h"
 #include "webrtc/base/gunit.h"
@@ -364,13 +365,14 @@ class DtlsTestClient : public sigslot::has_slots<> {
   }
 
   // Transport channel callbacks
-  void OnTransportChannelWritableState(cricket::TransportChannel* channel) {
-    LOG(LS_INFO) << name_ << ": Channel '" << channel->component()
+  void OnTransportChannelWritableState(rtc::PacketTransport* pt) {
+    LOG(LS_INFO) << name_ << ": Channel '" << pt->component()
                  << "' is writable";
   }
 
-  void OnTransportChannelReadPacket(cricket::TransportChannel* channel,
-                                    const char* data, size_t size,
+  void OnTransportChannelReadPacket(rtc::PacketTransport* pt,
+                                    const char* data,
+                                    size_t size,
                                     const rtc::PacketTime& packet_time,
                                     int flags) {
     uint32_t packet_num = 0;
@@ -382,7 +384,7 @@ class DtlsTestClient : public sigslot::has_slots<> {
     ASSERT_EQ(expected_flags, flags);
   }
 
-  void OnTransportChannelSentPacket(cricket::TransportChannel* channel,
+  void OnTransportChannelSentPacket(rtc::PacketTransport* pt,
                                     const rtc::SentPacket& sent_packet) {
     sent_packet_ = sent_packet;
   }
@@ -390,8 +392,9 @@ class DtlsTestClient : public sigslot::has_slots<> {
   rtc::SentPacket sent_packet() const { return sent_packet_; }
 
   // Hook into the raw packet stream to make sure DTLS packets are encrypted.
-  void OnFakeTransportChannelReadPacket(cricket::TransportChannel* channel,
-                                        const char* data, size_t size,
+  void OnFakeTransportChannelReadPacket(rtc::PacketTransport* pt,
+                                        const char* data,
+                                        size_t size,
                                         const rtc::PacketTime& time,
                                         int flags) {
     // Flags shouldn't be set on the underlying TransportChannel packets.