Auto merge of #16344 - hiikezoe:animation-only-restyle-fix, r=emilio,heycam

Call process_animation only if it's not animation-only restyles

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This is a PR of https://bugzilla.mozilla.org/show_bug.cgi?id=1354426

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because it's for stylo.

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components/style/matching.rs

@@ -433,7 +433,7 @@ trait PrivateMatchMethods: TElement {
                                                    &pseudo_style);
 
         // Handle animations.
-        if animate {
+        if animate && !context.shared.traversal_flags.for_animation_only() {
             self.process_animations(context,
                                     &mut old_values,
                                     &mut new_values,
@@ -906,7 +906,7 @@ pub trait MatchMethods : TElement {
 
     /// Updates the rule nodes without re-running selector matching, using just
     /// the rule tree. Returns true if the rule nodes changed.
-    fn cascade_with_replacements(&self,
+    fn replace_rules(&self,
                      hint: RestyleHint,
                      context: &StyleContext<Self>,
                      data: &mut AtomicRefMut<ElementData>)

components/style/traversal.rs

@@ -711,7 +711,7 @@ fn compute_style<E, D>(_traversal: &D,
         }
         CascadeWithReplacements(hint) => {
             let _rule_nodes_changed =
-                element.cascade_with_replacements(hint, context, &mut data);
+                element.replace_rules(hint, context, &mut data);
             element.cascade_primary_and_pseudos(context, &mut data);
         }
         CascadeOnly => {