Add overhead per packet observer to the rtp_sender.

webrtc/modules/rtp_rtcp/source/rtp_sender.h

Index: webrtc/modules/rtp_rtcp/source/rtp_sender.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.h b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
index 09bcebc6403f013f576b1d49a54ca3c0dde5fb29..0886cc3ada03da46dc3126f4068ac82a097e148c 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
@@ -35,6 +35,7 @@
 
 namespace webrtc {
 
+class OverheadSizeObserver;
 class RateLimiter;
 class RtcEventLog;
 class RtpPacketToSend;
@@ -57,7 +58,8 @@ class RTPSender {
             SendSideDelayObserver* send_side_delay_observer,
             RtcEventLog* event_log,
             SendPacketObserver* send_packet_observer,
-            RateLimiter* nack_rate_limiter);
+            RateLimiter* nack_rate_limiter,
+            OverheadSizeObserver* overhead_size_observer);
 
   ~RTPSender();
 
@@ -210,6 +212,8 @@ class RTPSender {
   void SetRtxRtpState(const RtpState& rtp_state);
   RtpState GetRtxRtpState() const;
 
+  void SetTransportOverhead(int transport_overhead);
+
  protected:
   int32_t CheckPayloadType(int8_t payload_type, RtpVideoCodecTypes* video_type);
 
@@ -255,6 +259,10 @@ class RTPSender {
                       bool is_retransmit);
   bool IsFecPacket(const RtpPacketToSend& packet) const;
 
+  void AddPacketToTransportFeedback(uint16_t packet_id,
+                                    RtpPacketToSend* packet,
+                                    int probe_cluster_id);
+
   Clock* const clock_;
   const int64_t clock_delta_ms_;
   Random random_ GUARDED_BY(send_critsect_);
@@ -320,8 +328,11 @@ class RTPSender {
   uint32_t ssrc_rtx_ GUARDED_BY(send_critsect_);
   // Mapping rtx_payload_type_map_[associated] = rtx.
   std::map<int8_t, int8_t> rtx_payload_type_map_ GUARDED_BY(send_critsect_);
+  size_t transport_overhead_bytes_per_packet_ GUARDED_BY(send_critsect_);
+  size_t rtp_overhead_bytes_per_packet_ GUARDED_BY(send_critsect_);
 
   RateLimiter* const retransmission_rate_limiter_;
+  OverheadSizeObserver* overhead_size_observer_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RTPSender);
 };