Remove function declarations, members, and friend tests that are
no longer used. Reorder the member variables.
Bug: webrtc:7494
Change-Id: I8c24e2f4b9d9846e6d3fef4e2c998aa26f49f8c9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/282180
Reviewed-by: Alessio Bazzica <alessiob@webrtc.org>
Commit-Queue: Hanna Silen <silen@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38570}