GitLab

* Unified the logic around when to turn ambient mode off around
  screen off. This replaces the lid state, suspend state handlers.
* Fixed a crash during shutdown when image download is scheduled

Bug: b:162597832
Change-Id: Ie64e5464c37acda3e0fa638c9343e78c4dc0c17d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2333540Reviewed-by: Meilin Wang <meilinw@chromium.org>
Reviewed-by: Tao Wu <wutao@chromium.org>
Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795278}