This is a reland of b89144a4

Original change's description:
> Add pixel test for AccessibilityFocusHighlight based on FocusRingBrowserTest
>
> AX-Relnotes: n/a
>
> Bug: 1114959
> Change-Id: Ib6d9f51a04fa8059dc6bd6192d182b8e0244367d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2352451
> Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
> Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
> Reviewed-by: Joey Arhar <jarhar@chromium.org>
> Reviewed-by: Mason Freed <masonfreed@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#803007}

TBR=ellyjones@chromium.org,masonfreed@chromium.org,jarhar@chromium.org

Bug: 1114959
Change-Id: I1997496df505691103568989a9cbfaa38e4e9b0e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2388025Reviewed-by: Alice Boxhall <aboxhall@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804034}