It is a bit more flexible than the current implementation.
Also cleanup ChannelSend::GetRTT since it is not called from the receive stream anymore.
Bug: none
Change-Id: I4403c8b1840012f2287d189be934fd1069de85fb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/374160
Commit-Queue: Jakob Ivarsson <jakobi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#43728}