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

talk/media/webrtc/webrtcvideoengine2.cc

Index: talk/media/webrtc/webrtcvideoengine2.cc
diff --git a/talk/media/webrtc/webrtcvideoengine2.cc b/talk/media/webrtc/webrtcvideoengine2.cc
index 5ee0119dcf259b925b54037958b472456666e0ec..7239d7a3eadaf43fef7ba80739fe799e4eac4e1c 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -557,6 +557,11 @@ WebRtcVideoEngine2::WebRtcVideoEngine2()
   rtp_header_extensions_.push_back(
       RtpHeaderExtension(kRtpVideoRotationHeaderExtension,
                          kRtpVideoRotationHeaderExtensionDefaultId));
+  if (webrtc::field_trial::FindFullName("WebRTC-SendSideBwe") == "Enabled") {
+    rtp_header_extensions_.push_back(RtpHeaderExtension(
+        kRtpTransportSequenceNumberHeaderExtension,
+        kRtpTransportSequenceNumberHeaderExtensionDefaultId));
+  }
 }
 
 WebRtcVideoEngine2::~WebRtcVideoEngine2() {
@@ -1651,12 +1656,14 @@ bool WebRtcVideoChannel2::SendRtp(const uint8_t* data,
                                   size_t len,
                                   const webrtc::PacketOptions& options) {
   rtc::Buffer packet(data, len, kMaxRtpPacketLen);
-  return MediaChannel::SendPacket(&packet);
+  rtc::PacketOptions rtc_options;
+  rtc_options.packet_id = options.packet_id;
+  return MediaChannel::SendPacket(&packet, rtc_options);
 }
 
 bool WebRtcVideoChannel2::SendRtcp(const uint8_t* data, size_t len) {
   rtc::Buffer packet(data, len, kMaxRtpPacketLen);
-  return MediaChannel::SendRtcp(&packet);
+  return MediaChannel::SendRtcp(&packet, rtc::PacketOptions());
 }
 
 void WebRtcVideoChannel2::StartAllSendStreams() {