Extracted from cl https://codereview.webrtc.org/1766653002/, where AddOrUpdateSink results in a deadlock. BUG=webrtc:5426 Review URL: https://codereview.webrtc.org/1861633002 Cr-Commit-Position: refs/heads/master@{#12281}
Extracted from cl https://codereview.webrtc.org/1766653002/, where AddOrUpdateSink results in a deadlock. BUG=webrtc:5426 Review URL: https://codereview.webrtc.org/1861633002 Cr-Commit-Position: refs/heads/master@{#12281}