The lock screen apps background animation might still be in progress
when the note action state changes to kActive - thus, update to login
shelf buttons lock screen app related layout (showing only unlock
button) should be delayed until the animation is complete.

Ownership of the lock screen app controller is moved from lock
action handler layout manager to root window controller so the
login shelf view can get a reference to it in order to observe
background state changes.

Bug: 746596
Change-Id: Ie2f59bcaa2ac549fc2e60c3565a4092937bdbf80
Reviewed-on: https://chromium-review.googlesource.com/692590


Commit-Queue: Toni Barzic <tbarzic@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Cr-Commit-Position: refs/heads/master@{#508811}