Ignore ::-webkit-scrollbar styles when scrollbar-width is not auto

[lukewarlow]

9649486

Ignore ::-webkit-scrollbar styles when scrollbar-width is not auto
https://bugs.webkit.org/show_bug.cgi?id=257052

Reviewed by Tim Nguyen and Simon Fraser.

RenderStyle::hasCustomScrollbarStyle() returns true if a custom style
for the scrollbar has been set via ::-webkit-scrollbar and the value of
scrollbar-width is auto (default). This replaces usages of
hasPseudoStyle(PseudoId::Scrollbar)
so the standard properties for styling scrollbars take precedence over
the non-standard.

WPT tests are included.

* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-001-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-001.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-002-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-002.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-003-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-003.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-004-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-004.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-005-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-color-005.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-010-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-010.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-011-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-011.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-012-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-012.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-013-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-013.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-014-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-014.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-015-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-015.html: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-016-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-scrollbars/scrollbar-width-016.html: Added.
* LayoutTests/platform/ios-wk2/TestExpectations:
* LayoutTests/platform/mac-wk1/TestExpectations:
* Source/WebCore/page/LocalFrameView.cpp:
(WebCore::LocalFrameView::rootElementForCustomScrollbarPartStyle const):
(WebCore::LocalFrameView::createScrollbar):
(WebCore::LocalFrameView::canShowNonOverlayScrollbars const):
(WebCore::LocalFrameView::styleHidesScrollbarWithOrientation const):
* Source/WebCore/page/LocalFrameView.h:
* Source/WebCore/rendering/RenderBox.cpp:
(WebCore::RenderBox::canUseOverlayScrollbars const):
* Source/WebCore/rendering/RenderLayerScrollableArea.cpp:
(WebCore::RenderLayerScrollableArea::createScrollbar):
* Source/WebCore/rendering/RenderListBox.cpp:
(WebCore::RenderListBox::createScrollbar):
* Source/WebCore/rendering/RenderMenuList.cpp:
(RenderMenuList::createScrollbar):
* Source/WebCore/rendering/RenderSearchField.cpp:
(WebCore::RenderSearchField::createScrollbar):
* Source/WebCore/rendering/style/RenderStyle.h:
* Source/WebCore/rendering/style/RenderStyleInlines.h:
(WebCore::RenderStyle::hasCustomScrollbarStyle const):

Canonical link: https://commits.webkit.org/265129@main

3475ee2

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[lukewarlow]

WPT PR web-platform-tests/wpt#40276

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 41d5013)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	🧪 wpe-wk2
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🛠 gtk
	🧪 ios-wk2-wpt	🧪 mac-wk1	🧪 gtk-wk2
	🧪 api-ios	🧪 mac-wk2	🧪 api-gtk
	✅ 🛠 tv	🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	🧪 mac-wk2-stress
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash d35e969)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	❌ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 611dbab)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 8fa8319)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch
	✅ 🛠 watch-sim

[lukewarlow]

Just putting what I put in slack here WRT this behaviour choice:

This is the behaviour Chrome has gone for in its experimental implementation so I've matched that for interop reasons.
I think also honouring the standard properties rather than non standard is better for Firefox compatability and more in keeping with how CSS generally works.

Iirc the ::-webkit-scrollbar CSS is considered a mistake. So this approach could allow its removal (aside from maybe something like display: none working) in future.

Without scrollbar-color being implemented this would lead to scenarios where there's un-themed scrollbars where previously there were but I personally would consider that acceptable. And also I intend to Implement scrollbar-color as well

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 40ac705)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	❌ 🧪 ios-wk2	❌ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	❌ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 3475ee2)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🛠 gtk
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv	❌ 🧪 mac-AS-debug-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 265129@main (9649486): https://commits.webkit.org/265129@main

Reviewed commits have been landed. Closing PR #14440 and removing active labels.