Split StyleCache's rule matching data from its invalidation metadata.
Allow callers to build either payload independently. Style invalidation
queries no longer force a full rule cache rebuild, and rule matching
no longer builds invalidation metadata as a side effect.
Previously, callers often treated an absent rule cache as proof that no
style invalidation metadata existed. That made some invalidation paths
do nothing until something else had populated the rule cache first.
Build invalidation data before reading it instead, so these paths use
the metadata whenever stylesheet rules require it.
Rebaseline style invalidation counter expectations for the new lazy
build points. Flush setup style work in the structural :has() feature
filter test before measuring each mutation, so the recomputation
counters describe the mutation itself instead of leftover setup work.
Changing :active or :open used the broad style invalidation path, so
large subtrees were recomputed even when only the target element and
selector-matched relatives could be affected.
Reuse the :has() feature collector to keep conservative fallback for
observable :has() cases, then use pseudo-class property invalidation
for the common targeted path.
Element.cpp still contained the CSS logic for deciding whether an
invalidation set references features present on an element. Move that
matcher into CSS::Invalidation::InvalidationSetMatcher.
The helper uses Element's public API for classes, id, attributes,
pseudo-class state, and removed-attribute tracking. This keeps Element
focused on DOM state while CSS::Invalidation owns selector feature
matching.
Node.cpp currently knows too much about selector invalidation metadata
when deciding whether subtree mutations can affect :has() selectors.
Pull that logic into CSS/Invalidation/HasMutationFeatureCollector so DOM
mutation code can ask a focused helper instead of inspecting
StyleInvalidationData directly.
This is a behavior-preserving extraction. It keeps the existing
conservative fallbacks for featureless subtree-sensitive selectors and
still uses the existing element property matching helper for
pseudo-class metadata.
