style: Avoid hashing hashes.

These are the last instances I can find of us hashing the atoms hash.

components/style/gecko/data.rs

@@ -7,7 +7,6 @@
 use Atom;
 use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut};
 use dom::TElement;
-use fnv::FnvHashMap;
 use gecko::rules::{CounterStyleRule, FontFaceRule};
 use gecko_bindings::bindings::{self, RawServoStyleSet};
 use gecko_bindings::structs::{ServoStyleSheet, StyleSheetInfo, ServoStyleSheetInner};
@@ -17,6 +16,7 @@ use gecko_bindings::sugar::ownership::{HasArcFFI, HasBoxFFI, HasFFI, HasSimpleFF
 use invalidation::media_queries::{MediaListKey, ToMediaListKey};
 use media_queries::{Device, MediaList};
 use properties::ComputedValues;
+use selector_map::PrecomputedHashMap;
 use servo_arc::Arc;
 use shared_lock::{Locked, StylesheetGuards, SharedRwLockReadGuard};
 use stylesheet_set::StylesheetSet;
@@ -124,7 +124,7 @@ pub struct PerDocumentStyleDataImpl {
     pub font_faces: Vec<(Arc<Locked<FontFaceRule>>, Origin)>,
 
     /// Map for effective counter style rules.
-    pub counter_styles: FnvHashMap<Atom, Arc<Locked<CounterStyleRule>>>,
+    pub counter_styles: PrecomputedHashMap<Atom, Arc<Locked<CounterStyleRule>>>,
 }
 
 /// The data itself is an `AtomicRefCell`, which guarantees the proper semantics
@@ -143,7 +143,7 @@ impl PerDocumentStyleData {
             stylist: Stylist::new(device, quirks_mode.into()),
             stylesheets: StylesheetSet::new(),
             font_faces: vec![],
-            counter_styles: FnvHashMap::default(),
+            counter_styles: PrecomputedHashMap::default(),
         }))
     }
 

components/style/stylist.rs

@@ -22,7 +22,7 @@ use properties::{AnimationRules, PropertyDeclarationBlock};
 use properties::INHERIT_ALL;
 use properties::IS_LINK;
 use rule_tree::{CascadeLevel, RuleTree, StyleSource};
-use selector_map::{SelectorMap, SelectorMapEntry};
+use selector_map::{PrecomputedHashMap, SelectorMap, SelectorMapEntry};
 use selector_parser::{SelectorImpl, PerPseudoElementMap, PseudoElement};
 use selectors::attr::NamespaceConstraint;
 use selectors::bloom::BloomFilter;
@@ -98,7 +98,7 @@ pub struct Stylist {
     rule_tree: RuleTree,
 
     /// A map with all the animations indexed by name.
-    animations: FnvHashMap<Atom, KeyframesAnimation>,
+    animations: PrecomputedHashMap<Atom, KeyframesAnimation>,
 
     /// Applicable declarations for a given non-eagerly cascaded pseudo-element.
     /// These are eagerly computed once, and then used to resolve the new
@@ -168,7 +168,7 @@ pub struct ExtraStyleData<'a> {
     /// A list of effective font-face rules and their origin.
     pub font_faces: &'a mut Vec<(Arc<Locked<FontFaceRule>>, Origin)>,
     /// A map of effective counter-style rules.
-    pub counter_styles: &'a mut FnvHashMap<Atom, Arc<Locked<CounterStyleRule>>>,
+    pub counter_styles: &'a mut PrecomputedHashMap<Atom, Arc<Locked<CounterStyleRule>>>,
 }
 
 #[cfg(feature = "gecko")]
@@ -1329,7 +1329,7 @@ impl Stylist {
 
     /// Returns the map of registered `@keyframes` animations.
     #[inline]
-    pub fn animations(&self) -> &FnvHashMap<Atom, KeyframesAnimation> {
+    pub fn animations(&self) -> &PrecomputedHashMap<Atom, KeyframesAnimation> {
         &self.animations
     }