Wire up transport sequence number / send time callbacks to webrtc via libjingle.

webrtc/p2p/base/portinterface.h

Index: webrtc/p2p/base/portinterface.h
diff --git a/webrtc/p2p/base/portinterface.h b/webrtc/p2p/base/portinterface.h
index 3c246da58a2197d7c159a309d4fe24bc10aa5894..c80b37a4bc0b92f892b13811eb5aa77dd2a11a8b 100644
--- a/webrtc/p2p/base/portinterface.h
+++ b/webrtc/p2p/base/portinterface.h
@@ -14,6 +14,7 @@
 #include <string>
 
 #include "webrtc/p2p/base/transport.h"
+#include "webrtc/base/asyncpacketsocket.h"
 #include "webrtc/base/socketaddress.h"
 
 namespace rtc {
@@ -112,6 +113,9 @@ class PortInterface {
   sigslot::signal4<PortInterface*, const char*, size_t,
                    const rtc::SocketAddress&> SignalReadPacket;
 
+  // Emitted each time a packet is sent on this port.
+  sigslot::signal2<PortInterface*, const rtc::SentPacket&> SignalSentPacket;
+
   virtual std::string ToString() const = 0;
 
  protected: