Avoid broad document invalidation when adding or removing ordinary
document-owned or shadow-owned stylesheets. Reuse the targeted
StyleSheetInvalidation path for style rules, including shadow-host
escapes, pseudo-element-only selectors, and trailing-universal cases.
Keep the broad path for sheet contents whose effects are not captured
by selector invalidation alone, including @property, @font-face,
@font-feature-values, @keyframes, imported sheets, and top-level @layer
blocks. Broad-path shadow-root sheets still reach host-side consumers
through their active-scope effects.
When invalidate_owners() runs on a stylesheet scoped to a shadow root,
we previously dirtied the host and its light-DOM side too broadly. That
forced restyles on nodes the shadow-scoped stylesheet cannot match.
Inspect the sheet's effective selectors and dependent features up front.
Only dirty assigned nodes, the host, the host root, or host-side
animation consumers when the sheet can actually reach them, while
keeping purely shadow-local mutations inside the shadow tree.
Handle inline stylesheet @keyframes insertions without falling back to
broad owner invalidation. Recompute only elements whose computed
animation-name already references the inserted keyframes name.
Document-scoped insertions still walk the shadow-including tree so
existing shadow trees pick up inherited animations, and shadow-root
stylesheets fan out through the host root so :host combinators can
refresh host-side consumers as well. Also introduce the shared
ShadowRootStylesheetEffects analysis so later stylesheet mutation paths
can reuse the same per-scope escape classification.
Avoid forcing a full style update when a connected inline <style> sheet
inserts an ordinary style rule. Build a targeted invalidation set from
the inserted rule and walk only the affected roots instead.
Introduce the shared StyleSheetInvalidation helper so later stylesheet
mutation paths can reuse the same selector analysis and root application
logic. It handles trailing-universal selectors, pseudo-element-only
rightmost compounds, and shadow-host escapes through ::slotted(...) and
:host combinators.
Keep the broad invalidate_owners() path for constructed stylesheets and
other sheet kinds whose TreeScope interactions still require it.
