Reland Connect TurnPort and TCPPort to AsyncPacketSocket::SignalSentPacket.

webrtc/p2p/base/port.h

Index: webrtc/p2p/base/port.h
diff --git a/webrtc/p2p/base/port.h b/webrtc/p2p/base/port.h
index 57608b5b14deefb57277e9fa044c6d9ca9f1fbfb..436b1e7faafc2993f67e5905a35ef0e56f1f2cf2 100644
--- a/webrtc/p2p/base/port.h
+++ b/webrtc/p2p/base/port.h
@@ -280,7 +280,11 @@ class Port : public PortInterface, public rtc::MessageHandler,
                             const std::string& remote_ufrag);
 
   // Called when a packet has been sent to the socket.
-  void OnSentPacket(const rtc::SentPacket& sent_packet);
+  // This is made pure virtual to notify subclasses of Port that they MUST
+  // listen to AsyncPacketSocket::SignalSentPacket and then call
+  // PortInterface::OnSentPacket.
+  virtual void OnSentPacket(rtc::AsyncPacketSocket* socket,
+                            const rtc::SentPacket& sent_packet) = 0;
 
   // Called when the socket is currently able to send.
   void OnReadyToSend();