For go/mustash chrome browser code cannot call directly into ash. The
implementations of these visual effects have no chrome dependencies and
a few ash dependencies, so move them into ash.

Split the AccessibilityFocusRingController tests into a unit test (in
ash) and an integration test (in chrome).

Remove ash::AccessibilityDelegate::ClearFocusHighlight() as it isn't
needed anymore.

This CL mostly just moves files. It does not introduce the mojo
interfaces needed to make these features actually work with mash.

Bug: 594887
Test: ash_unittests, interactive_ui_tests
Change-Id: I7852f494467b77ab6f06658347a88b82a8b596c5
Reviewed-on: https://chromium-review.googlesource.com/671540


Commit-Queue: James Cook <jamescook@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503222}