style: Finer grained invalidation for attribute changes.

This should help out quite a bit with uBO, which has lots of very
general attribute selectors. We invalidate per attribute name rather
than using a SelectorMap, which prevents matching for attribute
selectors that can't have changed.

The idea is that this should be generally cheaper, though there are
cases where this would be a slight pesimization. For example, if there's
an attribute selector like:

  my-specific-element[my-attribute] { /* ... */ }

And you change `my-attribute` in an element that isn't a
`my-specific-element`, before that the SelectorMap would've prevented us
from selector-matching completely. Now we'd still run selector-matching
for that (though the matching would be pretty cheap).

However I think this should speed up things generally, let's see what
the perf tests think before landing this though.

Differential Revision: https://phabricator.services.mozilla.com/D76825

1 files changed, 0 insertions, 6 deletions

diff --git a/components/style/servo/selector_parser.rs b/components/style/servo/selector_parser.rs
index 7f8ac65089d..d8b84b13280 100644
--- a/components/style/servo/selector_parser.rs
+++ b/components/style/servo/selector_parser.rs
@@ -391,12 +391,6 @@ impl NonTSPseudoClass {
     pub fn needs_cache_revalidation(&self) -> bool {
         self.state_flag().is_empty()
     }
-
-    /// Returns true if the evaluation of the pseudo-class depends on the
-    /// element's attributes.
-    pub fn is_attr_based(&self) -> bool {
-        matches!(*self, NonTSPseudoClass::Lang(..))
-    }
 }
 
 /// The abstract struct we implement the selector parser implementation on top