commit db3231465d3d1a4f05c68e05935ad2085f855e11
author Philip Rogers <pdr@chromium.org> Thu Jan 03 21:01:30 2019
committer Commit Bot <commit-bot@chromium.org> Thu Jan 03 21:01:30 2019
tree 464a0ccf209de089916792efaf177c6f29d3672b
parent 031d7fa5ace7bf5102404a97eb938d37efda3000

Account for layout overflow when omitting overflow clip

When deciding whether an overflow clip paint property node is needed, we
previously checked if the visual overflow extended beyond the overflow clip
rect. This would miss cases when the visual overflow was empty (e.g.,
descendants with width: 0) but the content was still scrollable. This patch adds
a check for layout overflow.

While in the area, the condition for visual overflow has been refactored to make
the self-painting PaintLayer case a little clearer. The early-out for PaintLayer
descendants is required for correctness.

Bug: 918675
Change-Id: I41fe5fd71a957f196b5b8095965d4e361e535196
Reviewed-on: https://chromium-review.googlesource.com/c/1393885
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619749}