This will allow RtcpPackets to be sent in a more generic way where the
PacketRouter does not have to know about the type.
App::SetSsrc is replaced with SetSenderSsrc
Bug: webrtc:10742
Change-Id: I9fa18d408250f15818dc6898093d9b116603facb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/156166
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29420}