Bug 1889109: Part 2 - Mark all elements considering scoped styles. r=firefox-style-system-reviewers,emilio

This lets us avoid having to run scope matching for revalidation
for elements that don't match scoped styles.

Differential Revision: https://phabricator.services.mozilla.com/D212726

servo/components/style/properties/computed_value_flags.rs

@@ -126,6 +126,9 @@ bitflags! {
 
         /// Whether there are author-specific rules for text `color`.
         const HAS_AUTHOR_SPECIFIED_TEXT_COLOR = 1 << 25;
+
+        /// Whether this style considered a scope style rule.
+        const CONSIDERED_SCOPED_STYLE = 1 << 26;
     }
 }
 
@@ -158,7 +161,8 @@ impl ComputedValueFlags {
     /// Flags that are an input to the cascade.
     #[inline]
     fn cascade_input_flags() -> Self {
-        Self::USES_VIEWPORT_UNITS_ON_CONTAINER_QUERIES
+        Self::USES_VIEWPORT_UNITS_ON_CONTAINER_QUERIES |
+        Self::CONSIDERED_SCOPED_STYLE
     }
 
     /// Returns the flags that are always propagated to descendants.

servo/components/style/stylist.rs

@@ -2862,6 +2862,8 @@ impl CascadeData {
         element: E,
         context: &mut MatchingContext<E::Impl>,
     ) -> ScopeProximity {
+        context.extra_data.cascade_input_flags.insert(ComputedValueFlags::CONSIDERED_SCOPED_STYLE);
+
         let candidates = self.scope_condition_matches(
             rule.scope_condition_id,
             stylist,