This is a reland of commit 17a02a31d7d2897b75ad69fdac5d10e7475a5865.
This is the first part of supporting stream priorities, and adds the API
and very basic support for setting and retrieving the stream priority.
This commit doesn't in any way change the actual packet sending - the
specified priority values are stored, but not acted on.
This is all that is client visible, so clients can start using the API
as written, and they would never notice that things are missing.
Bug: webrtc:5696
Change-Id: I04d64a63cbaec67568496ad99667e14eba85f2e0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/264424
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37081}
7e897aeb92