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

webrtc/base/asyncpacketsocket.h

Index: webrtc/base/asyncpacketsocket.h
diff --git a/webrtc/base/asyncpacketsocket.h b/webrtc/base/asyncpacketsocket.h
index f0c221da1dec3fd4014be539224366d507fcac23..b6cd4a1b880c08f484d1385f231abc0d3cdb67b4 100644
--- a/webrtc/base/asyncpacketsocket.h
+++ b/webrtc/base/asyncpacketsocket.h
@@ -34,10 +34,11 @@ struct PacketTimeUpdateParams {
 // This structure holds meta information for the packet which is about to send
 // over network.
 struct PacketOptions {
-  PacketOptions() : dscp(DSCP_NO_CHANGE) {}
-  explicit PacketOptions(DiffServCodePoint dscp) : dscp(dscp) {}
+  PacketOptions() : dscp(DSCP_NO_CHANGE), packet_id(-1) {}
+  PacketOptions(DiffServCodePoint dscp) : dscp(dscp), packet_id(-1) {}
 
   DiffServCodePoint dscp;
+  int packet_id;  // 16 bits, -1 represents "not set".
   PacketTimeUpdateParams packet_time_params;
 };
 
@@ -61,6 +62,15 @@ inline PacketTime CreatePacketTime(int64 not_before) {
   return PacketTime(TimeMicros(), not_before);
 }
 
+struct SentPacket {
+  SentPacket() : packet_id(-1), send_time_ms(-1) {}
+  SentPacket(int32 packet_id, int64 send_time_ms)
+      : packet_id(packet_id), send_time_ms(send_time_ms) {}
+
+  int packet_id;
+  int64 send_time_ms;
+};
+
 // Provides the ability to receive packets asynchronously. Sends are not
 // buffered since it is acceptable to drop packets under high load.
 class AsyncPacketSocket : public sigslot::has_slots<> {
@@ -109,6 +119,10 @@ class AsyncPacketSocket : public sigslot::has_slots<> {
                    const SocketAddress&,
                    const PacketTime&> SignalReadPacket;
 
+  // Emitted each time a packet is sent.
+  sigslot::signal3<AsyncPacketSocket*, const SocketAddress&, const SentPacket&>
+      SignalPacketSent;

[stefan-webrtc, 2015/10/05 13:43:19]

I'm not sure if I actually need SocketAddress here, I suspect not? It doesn't
matter to me if the address changes, the packet ids are still the same. Or can
multiple peer connections share the same socket?

[pthatcher1, 2015/10/05 18:30:14]

You shouldn't care what socket it is, as long as the packet IDs don't overlap
between different transports (different audio and video streams if they are not
bundled).  If the IDs don't overlap, then you're fine.  However, the typical
style is to include the object as the first parameter.  So even though you don't
need it, it's consistent to include it.

[stefan-webrtc, 2015/10/07 16:55:25]

Acknowledged.

+
   // Emitted when the socket is currently able to send.
   sigslot::signal1<AsyncPacketSocket*> SignalReadyToSend;