[Async overflow scroll] Flashing content when scrolling async overflow with a negativ...
authorsimon.fraser@apple.com <simon.fraser@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Sun, 2 Jun 2019 03:01:47 +0000 (03:01 +0000)
committersimon.fraser@apple.com <simon.fraser@apple.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Sun, 2 Jun 2019 03:01:47 +0000 (03:01 +0000)
commit1607ea6b699c02218720748503f1eafca0084a74
tree32dad056dc84b4a9c0a62cb214f9c78735245f8b
parent1415e8811dcda5e27841ecd92af28d820591fa09
[Async overflow scroll] Flashing content when scrolling async overflow with a negative z-index child
https://bugs.webkit.org/show_bug.cgi?id=198458

Reviewed by Dean Jackson.

Source/WebCore:

Set the GraphicsLayerPaintOverflowContents phase on the foreground layer in a composited overflow scroller,
which prevents clipping to the visible region, fixing scrolling flashes.

Tested by compositing/overflow/stacking-context-composited-scroller-with-foreground-paint-phases.html

* rendering/RenderLayerBacking.cpp:
(WebCore::RenderLayerBacking::updatePaintingPhases):

LayoutTests:

* compositing/overflow/stacking-context-composited-scroller-with-foreground-paint-phases-expected.txt:
* platform/ios-wk2/compositing/overflow/stacking-context-composited-scroller-with-foreground-paint-phases-expected.txt:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@246019 268f45cc-cd09-0410-ab3c-d52691b4dbfc
LayoutTests/ChangeLog
LayoutTests/compositing/overflow/stacking-context-composited-scroller-with-foreground-paint-phases-expected.txt
LayoutTests/platform/ios-wk2/compositing/overflow/stacking-context-composited-scroller-with-foreground-paint-phases-expected.txt
Source/WebCore/ChangeLog
Source/WebCore/rendering/RenderLayerBacking.cpp