GitLab

Previously monitored prefs only if ambient mode was already enabled.

BUG=b:169579102

Cq-Include-Trybots: luci.chrome.try:linux-chromeos-chrome
Change-Id: I287ab1e710b8c45b6fb2b90ba6879fb5726fc2f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2535111
Commit-Queue: Jeffrey Young <cowmoo@chromium.org>
Reviewed-by: Xiaohui Chen <xiaohuic@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827863}