Bug 1863562 [wpt PR 42997] - Reland "Add argument to IsFocusable() for a11y use only...

Bug 1863562 [wpt PR 42997] - Reland "Add argument to IsFocusable() for a11y use only", a=testonly

Automatic update from web-platform-tests
Reland "Add argument to IsFocusable() for a11y use only"

This is a reland of commit 5d2f4b32390faebd8b8da13ad7856d482b2477a1

Patchset 1 is the original patch. The current CL removes the behavior
change for <dialog>, and keeps the old behavior. I still believe this
isn't quite right, but I'd like to get the a11y/crash benefit of
the rest of the patch so I'll follow up with a fix for dialog if
I can come up with one.

Original change's description:
> Add argument to IsFocusable() for a11y use only
>
> This CL adds this:
>
>   virtual bool IsFocusable(
>       bool disallow_layout_updates_for_accessibility_only = false);
>
> for use by a11y code, which sometimes hits the CHECK for clean
> layout. When this bool is true (default false), layout will not
> be updated to check focusability, and possibly-stale layout objects
> will be used.
>
> Bug: 1485059, 1489580, 1492703
> Change-Id: I7f8b73a74341e6dad04102c327b1b8ce99a2ef1d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4959753
> Auto-Submit: Mason Freed <masonf@chromium.org>
> Commit-Queue: Mason Freed <masonf@chromium.org>
> Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
> Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1213856}

Bug: 1485059, 1489580, 1492703
Bug: 1499838
Change-Id: I4e18099fdd98bf92be1fc829a763298541fbe267
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5008754
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1221779}

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wpt-commits: 46a99559f2d55c96927f97969afd32202304a209
wpt-pr: 42997