As it will be heavily modified in a follow-up change, it's refactored
as a separate commit to make commits small:
* Extracted code to separate AddPacket and CullOldPackets methods
* BuildFeedbackPacket now returns a packet. In the next iteration, it
might not, so it needs to be able to decide when to increment the
packet sequence number.
* Documented some existing fields.
The follow-up is in change I3dd58105f9fbfb111f176833cd4aa6b040c0e01d.
Bug: webrtc:12689
Change-Id: I5ad0aee5a7da008f9e209f7c13bf299c12f9d1f3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/217581
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33942}
7b4ee155f1