Reland "Fix fundamental compositing issue for scrollers with overlay controls"

This reverts commit 0a55f158.

Reason for revert: Reland the original CL with crbug.com/1286990 and
crbug.com/1287047 fixed, by not going through the atomic painting
code path for PaintPhase::kOverlayOverflowControls.

Original change's description:
> Revert "Fix fundamental compositing issue for scrollers with overlay controls"
>
> This reverts commit 30a60603.
>
> Reason for revert: The CL caused crbug.com/1286990. It may also cause
> hit testing problem of overlay overflow controls, especially
> resizers.
>
> Original change's description:
> > Fix fundamental compositing issue for scrollers with overlay controls
> >
> > Stop forcing scrollers with overlay controls (overlay scrollbars and
> > resizers) to be self-painting PaintLayers. Now overlay controls are
> > painted in three ways:
> > - (unchanged) If the overlay controls (of a non-stacking-context
> >   scroller) need reordering, i.e. need to be painted after some
> >   descendants in containing-block order but not in paint-order,
> >   the overlay controls are still painted in
> >   PaintLayerPainter::PaintChildren() of the containing stacking context.
> > - Otherwise:
> >   - (unchanged) if the scroller has a self-painting PaintLayer, the
> >     overlay controls are painted in
> >     PaintLayerPainter::PaintLayerContent() after all children.
> >   - (new) if the scroller doesn't have a self-painting PaintLayer,
> >     the overlay controls are painted in the foreground paint phase.
> >
> > Bug: 370604
> > Change-Id: Ifc0437f794ad57e860c8d73c6aeae06a81f58601
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3375382


> > Reviewed-by: Philip Rogers <pdr@chromium.org>
> > Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#958033}
>
> Bug: 370604
> Change-Id: Id8ba7d5114f966f6a1eeb25c840b6c715438dd76
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3385126
> Auto-Submit: Xianzhu Wang <wangxianzhu@chromium.org>
> Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
> Cr-Commit-Position: refs/heads/main@{#958470}

Bug: 1287408
Change-Id: If907fda0285513bde5f277be21940f7d4c244e4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3391921


Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#959826}