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

webrtc/p2p/base/transportchannel.h

Index: webrtc/p2p/base/transportchannel.h
diff --git a/webrtc/p2p/base/transportchannel.h b/webrtc/p2p/base/transportchannel.h
index 9b0ac7bd5bcae60bd95d6c1c5c264d363c2e1160..01270a5775fb66f1a840e68808fd3d69d0fe4342 100644
--- a/webrtc/p2p/base/transportchannel.h
+++ b/webrtc/p2p/base/transportchannel.h
@@ -18,6 +18,7 @@
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/p2p/base/candidate.h"
 #include "webrtc/p2p/base/candidatepairinterface.h"
+#include "webrtc/p2p/base/packettransportinterface.h"
 #include "webrtc/p2p/base/transport.h"
 #include "webrtc/p2p/base/transportdescription.h"
 #include "webrtc/base/asyncpacketsocket.h"
@@ -51,7 +52,7 @@ enum TransportChannelState {
 // between the two sides of a session.
 // TODO(deadbeef): This interface currently represents the unity of an ICE
 // transport and a DTLS transport. They need to be separated apart.
-class TransportChannel : public sigslot::has_slots<> {
+class TransportChannel : public rtc::PacketTransportInterface {
  public:
   TransportChannel(const std::string& transport_name, int component)
       : transport_name_(transport_name),
@@ -68,36 +69,20 @@ class TransportChannel : public sigslot::has_slots<> {
 
   const std::string& transport_name() const { return transport_name_; }
   int component() const { return component_; }
+  const std::string debug_name() const override {
+    return transport_name() + " " + std::to_string(component());
+  }
 
   // Returns the states of this channel.  Each time one of these states changes,
   // a signal is raised.  These states are aggregated by the TransportManager.
-  bool writable() const { return writable_; }
+  bool writable() const override { return writable_; }
   bool receiving() const { return receiving_; }
   DtlsTransportState dtls_state() const { return dtls_state_; }
-  sigslot::signal1<TransportChannel*> SignalWritableState;
-  // Emitted when the TransportChannel's ability to send has changed.
-  sigslot::signal1<TransportChannel*> SignalReadyToSend;
   sigslot::signal1<TransportChannel*> SignalReceivingState;
   // Emitted whenever DTLS-SRTP is setup which will require setting up a new
   // SRTP context.
   sigslot::signal2<TransportChannel*, DtlsTransportState> SignalDtlsState;
 
-  // Attempts to send the given packet.  The return value is < 0 on failure.
-  // TODO: Remove the default argument once channel code is updated.
-  virtual int SendPacket(const char* data, size_t len,
-                         const rtc::PacketOptions& options,
-                         int flags = 0) = 0;
-
-  // Sets a socket option on this channel.  Note that not all options are
-  // supported by all transport types.
-  virtual int SetOption(rtc::Socket::Option opt, int value) = 0;
-  // TODO(pthatcher): Once Chrome's MockTransportChannel implments
-  // this, remove the default implementation.
-  virtual bool GetOption(rtc::Socket::Option opt, int* value) { return false; }
-
-  // Returns the most recent error that occurred on this channel.
-  virtual int GetError() = 0;
-
   // Returns the current stats for this connection.
   virtual bool GetStats(ConnectionInfos* infos) = 0;
 
@@ -139,13 +124,6 @@ class TransportChannel : public sigslot::has_slots<> {
                                     uint8_t* result,
                                     size_t result_len) = 0;
 
-  // Signalled each time a packet is received on this channel.
-  sigslot::signal5<TransportChannel*, const char*,
-                   size_t, const rtc::PacketTime&, int> SignalReadPacket;
-
-  // Signalled each time a packet is sent on this channel.
-  sigslot::signal2<TransportChannel*, const rtc::SentPacket&> SignalSentPacket;
-
   // Deprecated by SignalSelectedCandidatePairChanged
   // This signal occurs when there is a change in the way that packets are
   // being routed, i.e. to a different remote location. The candidate