GitLab

ShelfBackgroundAnimator determined color by looking at both ShelfBackgroundType
and also the session state. ShelfBackgroundType was set from ShelfLayoutManager.

Both ShelfLayoutManager and ShelfBackgroundAnimator observed session state
changes and updated the shelf colors from that. This means that there were
multiple color updates, and beyond that the rendered background type could
diverge from what was requested by ShelfLayoutManager in the time between the
two callbacks.

Remove the ability for ShelfLayoutManager to observe session state changes, and
encode the needed information in ShelfBackgroundType. This simplifies control
flow and reduces complexity.

Bug: 857221
Change-Id: I173e8cc47d7f6f22123814d341a94749472f7932
Reviewed-on: https://chromium-review.googlesource.com/1168028
Commit-Queue: Jacob Dufault <jdufault@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Michael Wasserman <msw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#582259}