...from the Call class.
With minimal shifting of ownership of a few variables, we can
maintain their state fully on the worker thread, where they're used.
This change also removes the dependency on RWLockWrapper.
Bug: webrtc:11612
Change-Id: Ia14be5bd6b50bd0b32d04f078b1e283080c00a19
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176122
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31360}
0d4647dffe