GitLab

We are gonna add a flag to introduce a new type of blur animation on
the wallpaper for overview usages. This is a start to make the logics
more encapsulated. No functional changes.

Test: ash_unittests
Bug: none
Change-Id: I98ef63f957f6ebbcc2315a0f9472fcc536128c09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1838683
Commit-Queue: Sammie Quon <sammiequon@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702995}