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

webrtc/p2p/base/packettransportinterface.h

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_P2P_BASE_PACKETTRANSPORTINTERFACE_H_
 #define WEBRTC_P2P_BASE_PACKETTRANSPORTINTERFACE_H_
 
+#include <string>
+#include <vector>
+
+#include "webrtc/base/sigslot.h"
+#include "webrtc/base/socket.h"
+
 namespace cricket {
 class TransportChannel;
 }
 
 namespace rtc {
-typedef cricket::TransportChannel PacketTransportInterface;
-}
+struct PacketOptions;
+struct PacketTime;
+struct SentPacket;
+
+class PacketTransportInterface : public sigslot::has_slots<> {
+ public:
+  virtual ~PacketTransportInterface() {}
+
+  // Identify the object for logging and debug purpose.
+  virtual const std::string debug_name() const = 0;
+
+  // The transport has been established.
+  virtual bool writable() const = 0;
+
+  // Attempts to send the given packet.
+  // The return value is < 0 on failure. The return value in failure case is not
+  // descriptive. Depending on failure cause and implementation details
+  // GetError() returns an descriptive errno.h error value.
+  // This mimics posix socket send() or sendto() behavior.
+  // TODO(johan): Reliable, meaningful, consistent error codes for all
+  // implementations would be nice.
+  // TODO(johan): 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. 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 MockPacketTransportInterface implements
+  // 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;
+
+  // Emitted when the writable state, represented by |writable()|, changes.
+  sigslot::signal1<PacketTransportInterface*> SignalWritableState;
+
+  //  Emitted when the PacketTransportInterface is ready to send packets. "Ready
+  //  to send" is more sensitive than the writable state; a transport may be
+  //  writable, but temporarily not able to send packets. For example, the
+  //  underlying transport's socket buffer may be full, as indicated by
+  //  SendPacket's return code and/or GetError.
+  sigslot::signal1<PacketTransportInterface*> SignalReadyToSend;
+
+  // Signalled each time a packet is received on this channel.
+  sigslot::signal5<PacketTransportInterface*,
+                   const char*,
+                   size_t,
+                   const rtc::PacketTime&,
+                   int>
+      SignalReadPacket;
+
+  // Signalled each time a packet is sent on this channel.
+  sigslot::signal2<PacketTransportInterface*, const rtc::SentPacket&>
+      SignalSentPacket;
+};
+
+}  // namespace rtc
 
 #endif  // WEBRTC_P2P_BASE_PACKETTRANSPORTINTERFACE_H_