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