:empty selector with animation not working properly

[graouts]

319ecb9

:empty selector with animation not working properly
https://bugs.webkit.org/show_bug.cgi?id=269051
rdar://122838142

Reviewed by Antti Koivisto.

If an element is targeted by an animation, it may cause style updates with an `AnimationOnly` resolution type.
When `Style::TreeResolver::resolveElement()` is called for that element, `resetStyleRelations()` is called on
that element first under `Style::TreeResolver::resolveComposedTree()` while iterating through the composed tree.

If an `:empty` pseudo-class rule matches that element, that call to `resetStyleRelations()` will remove the
`StyleAffectedByEmpty` flag on that element, but it will not be recomputed under `resolveElement()` because when
`styleForStyleable()` is called the `AnimationOnly` resolution type will mean that we clone the cached last style
resolution style to return the `ResolvedStyle` value, clear of any relations.

We now avoid calling `resetStyleRelations()` if the resolution type is `AnimationOnly`, ensuring that relations
are preserved throughout animation updates.

* LayoutTests/imported/w3c/web-platform-tests/css/css-animations/empty-pseudo-class-with-animation-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-animations/empty-pseudo-class-with-animation.html: Added.
* Source/WebCore/style/StyleTreeResolver.cpp:
(WebCore::Style::TreeResolver::resolveComposedTree):

Canonical link: https://commits.webkit.org/275832@main

1923f33

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	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-skia
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🛠 watch
✅ 🛠 🧪 unsafe-merge	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash 1923f33)

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	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-skia
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🛠 watch
✅ 🛠 🧪 unsafe-merge	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 275832@main (319ecb9): https://commits.webkit.org/275832@main

Reviewed commits have been landed. Closing PR #25583 and removing active labels.