The class already clears the thread that's used in its dtor and consistently uses the same thread. Bug: webrtc:11908 Change-Id: I5ea8d00c2e59bf46c5b369be5b23cf1d8e1875c4 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/184060 Reviewed-by: Henrik Boström <hbos@webrtc.org> Commit-Queue: Tommi <tommi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#32097}