servo: Merge #17995 - style: Don't pre-fill eager pseudo-maps (from emilio:less-pseudo-maps); r=SimonSapin

This was needed long time ago for Servo's layout. But I don't think there's any
reason for doing this now.

Source-Repo: https://github.com/servo/servo
Source-Revision: f8abce8b72bf3fb09d39d6c7d708a79d1b89c9db

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 7974c18af7dc3873105bbe2b89ff98ca3deb3b49

servo/components/style/stylist.rs

@@ -1646,14 +1646,10 @@ struct PerOriginCascadeData {
 
 impl PerOriginCascadeData {
     fn new() -> Self {
-        let mut data = PerOriginCascadeData {
+        Self {
             element_map: SelectorMap::new(),
             pseudos_map: Default::default(),
-        };
-        SelectorImpl::each_eagerly_cascaded_pseudo_element(|pseudo| {
-            data.pseudos_map.insert(pseudo, SelectorMap::new());
-        });
-        data
+        }
     }
 
     #[inline]
@@ -1677,11 +1673,7 @@ impl PerOriginCascadeData {
     }
 
     fn clear(&mut self) {
-        self.element_map = SelectorMap::new();
-        self.pseudos_map = Default::default();
-        SelectorImpl::each_eagerly_cascaded_pseudo_element(|pseudo| {
-            self.pseudos_map.insert(pseudo, SelectorMap::new());
-        });
+        *self = Self::new();
     }
 
     fn has_rules_for_pseudo(&self, pseudo: &PseudoElement) -> bool {