Sequence- and RaceCheckers ensure thread safety, and show that these locks protect nothing. Bug: webrtc:15181 Change-Id: I7c26cd9aea5fa72ad9435de5ec1b9135ac22b1e8 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/305649 Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org> Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org> Reviewed-by: Per Kjellander <perkj@webrtc.org> Cr-Commit-Position: refs/heads/main@{#40345}