Change ReceiveStatistics to implement RtpPacketSinkInterface, part 2.

Delete the deprecated IncomingPacket method, and convert implementation
to use RtpPacketReceived rather than RTPHeader.

Part 1 was https://webrtc-review.googlesource.com/c/src/+/100104

Bug: webrtc:7135, webrtc:8016
Change-Id: Ib4840d947870403deea2f9067f847e4b0f182479
Reviewed-on: https://webrtc-review.googlesource.com/c/6762
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25648}

modules/rtp_rtcp/include/receive_statistics.h

@@ -56,13 +56,6 @@ class ReceiveStatistics : public ReceiveStatisticsProvider,
 
   static ReceiveStatistics* Create(Clock* clock);
 
-  // Updates the receive statistics with this packet.
-  // TODO(bugs.webrtc.org/8016): Deprecated. Delete as soon as
-  // downstream code is updated to use OnRtpPacket.
-  RTC_DEPRECATED
-  virtual void IncomingPacket(const RTPHeader& rtp_header,
-                              size_t packet_length) = 0;
-
   // Increment counter for number of FEC packets received.
   virtual void FecPacketReceived(const RtpPacketReceived& packet) = 0;