Regression(264098@main) HTMLFieldsetElement behavior for :enabled / :disabled CSS selectors is incorrect

[cdumez]

a6d354d

Regression(264098@main) HTMLFieldsetElement behavior for :enabled / :disabled CSS selectors is incorrect
https://bugs.webkit.org/show_bug.cgi?id=258078

Reviewed by Tim Nguyen.

264098@main updated HTMLFieldSetElement::isDisabledFormControl() to return false
since a fieldset element can never be disabled per the specification.

This had the side effect of affecting our behavior for :enabled / :disabled CSS
selectors, which relied on this function. However, the behavior of these CSS
selectors shouldn't have changed since they rely on the "actually disabled" state,
not the "disabled" state [1].

There were two issues here, some of our CSS selector logic was relying on
isDisabledFormControl() instead of isActuallyDisabled(). Also, 264098@main
shouldn't have changed the value returned by isActuallyDisabled() for
HTMLFieldsetElements.

This was pointed out at:
- whatwg/html#5886 (comment)

[1] https://html.spec.whatwg.org/multipage/semantics-other.html#selector-enabled
[2] https://html.spec.whatwg.org/multipage/semantics-other.html#selector-disabled
[3] https://html.spec.whatwg.org/multipage/semantics-other.html#concept-element-disabled
[4] https://html.spec.whatwg.org/multipage/form-elements.html#concept-fieldset-disabled

* LayoutTests/imported/w3c/web-platform-tests/html/semantics/selectors/pseudo-classes/disabled.html:
* LayoutTests/imported/w3c/web-platform-tests/html/semantics/selectors/pseudo-classes/enabled.html:
* Source/WebCore/css/SelectorCheckerTestFunctions.h:
(WebCore::matchesEnabledPseudoClass):
* Source/WebCore/html/HTMLElement.h:
* Source/WebCore/html/HTMLFieldSetElement.cpp:
(WebCore::HTMLFieldSetElement::isActuallyDisabled const):
* Source/WebCore/html/HTMLFieldSetElement.h:

Canonical link: https://commits.webkit.org/265166@main

a32e60b

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[webkit-early-warning-system]

EWS run on current version of this PR (hash a32e60b)

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✅ 🧪 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 265166@main (a6d354d): https://commits.webkit.org/265166@main

Reviewed commits have been landed. Closing PR #14959 and removing active labels.