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

webrtc/base/byteorder.h

Index: webrtc/base/byteorder.h
diff --git a/webrtc/base/byteorder.h b/webrtc/base/byteorder.h
index d907d9e41280dea3ad10aaed78f4ad8f8b730783..98a082feb8bfd5a318de81340e17a600678731b7 100644
--- a/webrtc/base/byteorder.h
+++ b/webrtc/base/byteorder.h
@@ -63,6 +63,12 @@ inline uint16 GetBE16(const void* memory) {
                              (Get8(memory, 1) << 0));
 }
 
+inline uint32 GetBE24(const void* memory) {
+  return (static_cast<uint32>(Get8(memory, 0)) << 16) |
+         (static_cast<uint32>(Get8(memory, 1)) << 8) |
+         (static_cast<uint32>(Get8(memory, 2)) << 0);
+}
+
 inline uint32 GetBE32(const void* memory) {
   return (static_cast<uint32>(Get8(memory, 0)) << 24) |
       (static_cast<uint32>(Get8(memory, 1)) << 16) |