Bug 1851090 - Remove layout.css.bucket-attribute-names.enabled pref r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D191571

modules/libpref/init/StaticPrefList.yaml

@@ -8231,14 +8231,6 @@
   mirror: always
   rust: true
 
-# Whether the rule hash is applied to attribute names too, not
-# only classes / id / namespaces / etc.
-- name: layout.css.bucket-attribute-names.enabled
-  type: RelaxedAtomicBool
-  value: true
-  mirror: always
-  rust: true
-
 # Set the number of device pixels per CSS pixel. A value <= 0 means choose
 # automatically based on user settings for the platform (e.g., "UI scale factor"
 # on Mac). If browser.display.os-zoom-behavior == 1, then a positive value

servo/components/style/selector_map.rs

@@ -153,7 +153,7 @@ impl<T> SelectorMap<T> {
             namespace_hash: HashMap::default(),
             rare_pseudo_classes: SmallVec::new(),
             other: SmallVec::new(),
-            bucket_attributes: static_prefs::pref!("layout.css.bucket-attribute-names.enabled"),
+            bucket_attributes: true,
             count: 0,
         }
     }