Change ReceiveStatistics to implement RtpPacketSinkInterface, part 1

Add new method OnRtpPacket, but leave
ReceiveStatisticsImpl::IncomingPacket and most of the implementation
unchanged. Deleting the old method and converting implementation from
RTPHeader to RtpPacketreceived is planned for a followup, after
downstream code is updated.

Bug: webrtc:7135, webrtc:8016
Change-Id: I697ec12804618859f8d69415622d1b957e1d0847
Reviewed-on: https://webrtc-review.googlesource.com/100104
Reviewed-by: Fredrik Solenberg <solenberg@webrtc.org>
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24889}
diff --git a/video/rtp_video_stream_receiver.h b/video/rtp_video_stream_receiver.h
index 5439887..b54d382 100644
--- a/video/rtp_video_stream_receiver.h
+++ b/video/rtp_video_stream_receiver.h
@@ -143,9 +143,7 @@
   void ReceivePacket(const RtpPacketReceived& packet);
   // Parses and handles RED headers.
   // This function assumes that it's being called from only one thread.
-  void ParseAndHandleEncapsulatingHeader(const uint8_t* packet,
-                                         size_t packet_length,
-                                         const RTPHeader& header);
+  void ParseAndHandleEncapsulatingHeader(const RtpPacketReceived& packet);
   void NotifyReceiverOfEmptyPacket(uint16_t seq_num);
   void UpdateHistograms();
   bool IsRedEnabled() const;