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

talk/media/sctp/sctpdataengine.h

Index: talk/media/sctp/sctpdataengine.h
diff --git a/talk/media/sctp/sctpdataengine.h b/talk/media/sctp/sctpdataengine.h
index 451c00d5bac62ced22c132e6292fecd85ce7e1ae..5e579f6033372dc2b43f694694a99e5dbd3a82e0 100644
--- a/talk/media/sctp/sctpdataengine.h
+++ b/talk/media/sctp/sctpdataengine.h
@@ -168,6 +168,8 @@ class SctpDataMediaChannel : public DataMediaChannel,
   virtual void OnPacketReceived(rtc::Buffer* packet,
                                 const rtc::PacketTime& packet_time);
 
+  virtual void OnPacketSent(const rtc::SentPacket& packet_sent) {}
+
   // Exposed to allow Post call from c-callbacks.
   rtc::Thread* worker_thread() const { return worker_thread_; }