[Reland] Element::VisibleBoundsInLocalRoot performs clipping

Reland Note: Reverted CL in first Patchset. It missed updating the
mac14-arm64 expectation.

VisibleBoundsRespectingClipsInLocalRoot was added in
https://crrev.com/c/6525508 as it was urgent but the real desire is for
VisibleBoundsInLocalRoot to have the overflow clipping behavior. This CL
makes the change to unify these two method behind a flag (as there may
be compat issues). Assuming this lands safely we can merge the two
methods.

VisibleBoundsInLocalRoot clips to ancestor frame rects but not to any
element clips (e.g. overflow:hidden). This change performs the entire
mapping using MapToVisualRectInAncestorSpace which does apply these
clips. The change is flag guarded in case of compatibility issues.

Making this change broke HTMLSelectElementTest.VisibleBoundsInLocalRoot
This is because MapToVisualRectInAncestorSpace causes the
subpixel-positioned rect to expand which can cause a select drop down to
appear detached from the element. This is why this function was using a
rounded absolute rect. This comes from https://crrev.com/1268243002. The
bug here appears to be coming from LayoutBox::ApplyBoxClips which
unnecessarily(?) snaps to pixels.

The spat-nav changes came from https://crrev.com/c/1243246 - the
IsOffscreen function no longer checks VisibleContentRect so only the
TODO is removed there stale test expectations can now be removed.
Technically SpatNav's NodeRectInRootFrame could now just be replaced by
VisibleBoundsInLocalRoot except that it has an edge-case for border
insets; its necessity is unclear.

Bug: 41417572,415110566
Change-Id: I5b8e7457731689d7721a15943f1d01508045cc1e
Include-Ci-Only-Tests: chromium.mac:mac14-arm64-rel-tests|blink_web_tests
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6617920
Reviewed-by: Philip Rogers <pdr@chromium.org>
Auto-Submit: David Bokan <bokan@chromium.org>
Commit-Queue: David Bokan <bokan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1469624}