GitLab

Set CCA window can consume volume button. Add new mojo API monitoring tablet
mode state. Trigger camera shutter when CCA window receive volume button event
in tablet mode.

Design doc: go/cros-camera:dd:cca-volume-button-shutter

Bug: 1024118
Test: Manually test shutter triggered after clicking volume button in
tablet/non-tablet mode

Change-Id: I8b6730773abae7741e90e676abc1a196f6289668
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2089111Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Wei Lee <wtlee@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Kuo Jen Wei <inker@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760369}