GitLab

If the media session feature is enabled then use the
media session service to control playback when the
play/pause media key is pressed.

BUG=894255

Change-Id: I5c34b24536456e4fcacabed6f4a8d2aa9f5d0ec5
Reviewed-on: https://chromium-review.googlesource.com/c/1278147
Commit-Queue: Becca Hughes <beccahughes@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600839}