Moves ui_controls to OnceCallback

BUG=714018
TEST=none

Change-Id: Ia0dadc31d6713b3df042d5f434bfa2165146b072
Reviewed-on: https://chromium-review.googlesource.com/946855
Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#540688}
25 files changed