For simplicity and flexibility on audio only API, it deemed to be better to trim off all audio unrelated logic to serve the purpose. Bug: webrtc:11251 Change-Id: I40e3eba2714c171f7c98b158303a7b3f744ceb78 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/169462 Reviewed-by: Per Åhgren <peah@webrtc.org> Reviewed-by: Patrik Höglund <phoglund@webrtc.org> Reviewed-by: Sebastian Jansson <srte@webrtc.org> Commit-Queue: Patrik Höglund <phoglund@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30922}