Delete unneeded forward declares of RtpReceiver

Bug: webrtc:7135
Change-Id: I1ca8537248ed5c87f8913263c680e0a5a5544130
Reviewed-on: https://webrtc-review.googlesource.com/94506
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24353}

modules/rtp_rtcp/include/rtp_rtcp.h

diff --git a/modules/rtp_rtcp/include/rtp_rtcp.h b/modules/rtp_rtcp/include/rtp_rtcp.h
index 94237e0..f982a9b 100644
--- a/modules/rtp_rtcp/include/rtp_rtcp.h
+++ b/modules/rtp_rtcp/include/rtp_rtcp.h
@@ -33,7 +33,6 @@
 class ReceiveStatisticsProvider;
 class RemoteBitrateEstimator;
 class RtcEventLog;
-class RtpReceiver;
 class Transport;
 class VideoBitrateAllocationObserver;
 

video/rtp_video_stream_receiver.h

diff --git a/video/rtp_video_stream_receiver.h b/video/rtp_video_stream_receiver.h
index b647bae..efd7662 100644
--- a/video/rtp_video_stream_receiver.h
+++ b/video/rtp_video_stream_receiver.h
@@ -47,7 +47,6 @@
 class ReceiveStatisticsProxy;
 class RtcpRttStats;
 class RtpPacketReceived;
-class RtpReceiver;
 class Transport;
 class UlpfecReceiver;