GainControlImpl was inited with two refs to the APM capture lock. As a
result, it could modify member vars without holding the render
lock. The Process and Analyze calls are not affected, because they are
made from audio_processing_impl when APM holds both locks.
Bug: webrtc:9354
Change-Id: I814b69602280921dda9dc45ffcbddb38de4a3394
Reviewed-on: https://webrtc-review.googlesource.com/84182
Reviewed-by: Max Morin <maxmorin@webrtc.org>
Commit-Queue: Alex Loiko <aleloi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23677}