Calls OnPacketsAcknowledged on RtpRtcp instead of RTPSender directly.

This prepares for splitting RtpSenderEgress out of RTPSender.
For context, see:
https://webrtc-review.googlesource.com/c/src/+/158020

Bug: webrtc:11036
Change-Id: I6d385ba255ce23f4c6685a3737eeb243ce2ec6ff
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158201
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29601}
diff --git a/modules/rtp_rtcp/source/rtp_rtcp_impl.cc b/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
index c7cbf50..f490439 100644
--- a/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
+++ b/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
@@ -342,6 +342,12 @@
   return rtp_sender_->TrySendPacket(packet, pacing_info);
 }
 
+void ModuleRtpRtcpImpl::OnPacketsAcknowledged(
+    rtc::ArrayView<const uint16_t> sequence_numbers) {
+  RTC_DCHECK(rtp_sender_);
+  rtp_sender_->OnPacketsAcknowledged(sequence_numbers);
+}
+
 bool ModuleRtpRtcpImpl::SupportsPadding() const {
   return rtp_sender_->SupportsPadding();
 }