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

webrtc/p2p/base/dtlstransportchannel.cc

Index: webrtc/p2p/base/dtlstransportchannel.cc
diff --git a/webrtc/p2p/base/dtlstransportchannel.cc b/webrtc/p2p/base/dtlstransportchannel.cc
index bba7eb9de7f8f22504d3b045a1af54b05f0bee7b..62c4dc16ed674de4f79c4eae06b49ed4eb72fc21 100644
--- a/webrtc/p2p/base/dtlstransportchannel.cc
+++ b/webrtc/p2p/base/dtlstransportchannel.cc
@@ -101,6 +101,8 @@ DtlsTransportChannelWrapper::DtlsTransportChannelWrapper(
       &DtlsTransportChannelWrapper::OnWritableState);
   channel_->SignalReadPacket.connect(this,
       &DtlsTransportChannelWrapper::OnReadPacket);
+  channel_->SignalSentPacket.connect(
+      this, &DtlsTransportChannelWrapper::OnSentPacket);
   channel_->SignalReadyToSend.connect(this,
       &DtlsTransportChannelWrapper::OnReadyToSend);
   channel_->SignalGatheringState.connect(
@@ -510,6 +512,15 @@ void DtlsTransportChannelWrapper::OnReadPacket(
   }
 }
 
+void DtlsTransportChannelWrapper::OnSentPacket(
+    TransportChannel* channel,
+    const rtc::SentPacket& sent_packet) {
+  ASSERT(rtc::Thread::Current() == worker_thread_);
+  ASSERT(channel == channel_);

[pbos-webrtc, 2015/10/12 20:48:00]

Is this assert really good? If this can't be changed in runtime while things are
in the queue then what's the point of it being mutable?

[pthatcher1, 2015/10/13 05:31:13]

channel_ never changes, and never should.  I believe we could mark it const.

[stefan-webrtc, 2015/10/13 08:09:20]

Done.

+
+  SignalSentPacket(this, sent_packet);
+}
+
 void DtlsTransportChannelWrapper::OnReadyToSend(TransportChannel* channel) {
   if (writable()) {
     SignalReadyToSend(this);