[:has() pseudo-class] Collect invalidation selectors for child invalidation

[:has() pseudo-class] Collect invalidation selectors for child invalidation
https://bugs.webkit.org/show_bug.cgi?id=235103

Reviewed by Dean Jackson.

Collect selectors we can use to test if :has status actually changed before invalidating.

This patch doesn't yet use the the selector.

* style/ChildChangeInvalidation.cpp:
(WebCore::Style::ChildChangeInvalidation::invalidateForChangedElement):

Use the pseudo class invalidation keys for looking up :has selectors too
instead of having a custom mechanism for doing the same thing.

* style/PseudoClassChangeInvalidation.cpp:
(WebCore::Style::makePseudoClassInvalidationKeys):
* style/PseudoClassChangeInvalidation.h:
* style/RuleFeature.cpp:
(WebCore::Style::RuleFeatureSet::recursivelyCollectFeaturesFromSelector):

Always return a selector for consistency.

(WebCore::Style::makePseudoClassInvalidationKey):
(WebCore::Style::RuleFeatureSet::collectFeatures):
(WebCore::Style::RuleFeatureSet::add):
(WebCore::Style::RuleFeatureSet::clear):
(WebCore::Style::RuleFeatureSet::shrinkToFit):
* style/RuleFeature.h:
* style/StyleScopeRuleSets.cpp:
(WebCore::Style::ScopeRuleSets::collectFeatures const):
(WebCore::Style::ScopeRuleSets::hasPseudoClassInvalidationRuleSets const):
(WebCore::Style::ScopeRuleSets::tagInvalidationRuleSets const): Deleted.

We don't need keep around tag rule sets anymore.

* style/StyleScopeRuleSets.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@287973 268f45cc-cd09-0410-ab3c-d52691b4dbfc