GitLab

To support the "stop" event generated by the Bluetooth devices with
AVRCP (Audio/Video Remote Control Profile), add handling for the stop
key.

BUG=b/147367020

Change-Id: I4bc9efa74173d8ffeab0affb4d685bc587f07616
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2063809Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Commit-Queue: Michael Sun <michaelfsun@google.com>
Cr-Commit-Position: refs/heads/master@{#743143}