Use SMIL override value that has been processed during animation-only restyles for normal restyle.

In the case where we process an element which has SMIL animations in normal travesal
the SMIL styles must have been computed in animation-only restyles. So we
have only to pick the computed styles instead of recomputing it.

components/style/data.rs

@@ -6,12 +6,12 @@
 
 use context::SharedStyleContext;
 use dom::TElement;
-use properties::ComputedValues;
+use properties::{ComputedValues, PropertyDeclarationBlock};
 use properties::longhands::display::computed_value as display;
 use restyle_hints::{HintComputationContext, RestyleReplacements, RestyleHint};
 use rule_tree::StrongRuleNode;
 use selector_parser::{EAGER_PSEUDO_COUNT, PseudoElement, RestyleDamage};
-use shared_lock::StylesheetGuards;
+use shared_lock::{Locked, StylesheetGuards};
 use std::fmt;
 use stylearc::Arc;
 use traversal::TraversalFlags;
@@ -558,4 +558,17 @@ impl ElementData {
     pub fn restyle_mut(&mut self) -> &mut RestyleData {
         self.get_restyle_mut().expect("Calling restyle_mut without RestyleData")
     }
+
+    /// Returns SMIL overriden value if exists.
+    pub fn get_smil_override(&self) -> Option<&Arc<Locked<PropertyDeclarationBlock>>> {
+        if cfg!(feature = "servo") {
+            // Servo has no knowledge of a SMIL rule, so just avoid looking for it.
+            return None;
+        }
+
+        match self.get_styles() {
+            Some(s) => s.primary.rules.get_smil_animation_rule(),
+            None => None,
+        }
+    }
 }

components/style/matching.rs

@@ -736,30 +736,32 @@ pub trait MatchMethods : TElement {
 
         let stylist = &context.shared.stylist;
         let style_attribute = self.style_attribute();
-        let smil_override = self.get_smil_override();
-        let animation_rules = self.get_animation_rules();
-        let bloom = context.thread_local.bloom_filter.filter();
+        {
+            let smil_override = data.get_smil_override();
+            let animation_rules = self.get_animation_rules();
+            let bloom = context.thread_local.bloom_filter.filter();
 
 
-        let map = &mut context.thread_local.selector_flags;
-        let mut set_selector_flags = |element: &Self, flags: ElementSelectorFlags| {
-            self.apply_selector_flags(map, element, flags);
-        };
+            let map = &mut context.thread_local.selector_flags;
+            let mut set_selector_flags = |element: &Self, flags: ElementSelectorFlags| {
+                self.apply_selector_flags(map, element, flags);
+            };
 
-        let mut matching_context =
-            MatchingContext::new(MatchingMode::Normal, Some(bloom));
+            let mut matching_context =
+                MatchingContext::new(MatchingMode::Normal, Some(bloom));
 
-        // Compute the primary rule node.
-        stylist.push_applicable_declarations(self,
-                                             implemented_pseudo.as_ref(),
-                                             style_attribute,
-                                             smil_override,
-                                             animation_rules,
-                                             &mut applicable_declarations,
-                                             &mut matching_context,
-                                             &mut set_selector_flags);
+            // Compute the primary rule node.
+            stylist.push_applicable_declarations(self,
+                                                 implemented_pseudo.as_ref(),
+                                                 style_attribute,
+                                                 smil_override,
+                                                 animation_rules,
+                                                 &mut applicable_declarations,
+                                                 &mut matching_context,
+                                                 &mut set_selector_flags);
 
-        *relations = matching_context.relations;
+            *relations = matching_context.relations;
+        }
 
         let primary_rule_node =
             compute_rule_node::<Self>(stylist.rule_tree(),

components/style/rule_tree/mod.rs

@@ -1128,6 +1128,30 @@ impl StrongRuleNode {
         }
         result
     }
+
+    /// Returns PropertyDeclarationBlock for this node.
+    /// This function must be called only for animation level node.
+    fn get_animation_style(&self) -> &Arc<Locked<PropertyDeclarationBlock>> {
+        debug_assert!(self.cascade_level().is_animation(),
+                      "The cascade level should be an animation level");
+        match *self.style_source().unwrap() {
+            StyleSource::Declarations(ref block) => block,
+            StyleSource::Style(_) => unreachable!("animating style should not be a style rule"),
+        }
+    }
+
+    /// Returns SMIL override declaration block if exists.
+    pub fn get_smil_animation_rule(&self) -> Option<&Arc<Locked<PropertyDeclarationBlock>>> {
+        if cfg!(feature = "servo") {
+            // Servo has no knowledge of a SMIL rule, so just avoid looking for it.
+            return None;
+        }
+
+        self.self_and_ancestors()
+            .take_while(|node| node.cascade_level() >= CascadeLevel::SMILOverride)
+            .find(|node| node.cascade_level() == CascadeLevel::SMILOverride)
+            .map(|node| node.get_animation_style())
+    }
 }
 
 /// An iterator over a rule node and its ancestors.