Add RemoteEstimatorProxy for capturing receive times

webrtc/modules/pacing/include/packet_router.h

Index: webrtc/modules/pacing/include/packet_router.h
diff --git a/webrtc/modules/pacing/include/packet_router.h b/webrtc/modules/pacing/include/packet_router.h
index e7d630eb2feecaa1943fdbffdf785110c359428b..c181ec094aebfc3a3b74bcfcbf03ee817b9d8c9f 100644
--- a/webrtc/modules/pacing/include/packet_router.h
+++ b/webrtc/modules/pacing/include/packet_router.h
@@ -19,6 +19,7 @@
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/pacing/include/paced_sender.h"
+#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 
 namespace webrtc {
 
@@ -45,6 +46,9 @@ class PacketRouter : public PacedSender::Callback {
   void SetTransportWideSequenceNumber(uint16_t sequence_number);
   uint16_t AllocateSequenceNumber();
 
+  // Send transport feedback packet to send-side.
+  virtual bool SendFeedback(rtcp::TransportFeedback* packet);

[stefan-webrtc, 2015/09/04 07:31:36]

Isn't PacketRouter actually living on the send side? Feels a bit confusing to
me. A receive shouldn't need a PacketRouter?

[sprang_webrtc, 2015/09/04 13:29:44]

Receive times are collected on a call-level, no in the rtp module, so we don't
have a natural way to send the transport feedback rtcp packet back to the send
side. The packet router will find a suitable rtcp sender in a similar manner to
how i finds a suitable rtp sender for the payload on the send side.

[stefan-webrtc, 2015/09/07 10:12:21]

Ok, maybe that is reasonable. How is it set up with the correct modules?

[sprang_webrtc, 2015/09/07 11:14:35]

Modules that can send rtcp are added to this router even if they don't send rtp
payload. That change probably ended up in one of the other CL's in the
pipeline...

+
  private:
   rtc::CriticalSection modules_lock_;
   // Map from ssrc to sending rtp module.