This groups functions for WebRtcVideoSendChannel and
WebRtcVideoReceiveChannel together, rather than interspersing them.
Bug: webrtc:13931
Change-Id: Iecb5bac18e1d370331e9eb546c6b2fde4d92963f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/309460
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40312}