GitLab

1. Use next_unlock_time as display time in lock screen.
2. Refresh screen time usage based on GetExpectedResetTime
3. Save time related states in kScreenTimeLastState since these are used
by the processor.

Bug: 823536
Change-Id: I9eae909ac79397cd3d0d61d7b5e85127292f7105
Reviewed-on: https://chromium-review.googlesource.com/1115759Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Xiaoyin Hu <xiaoyinh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#571586}