1 files changed, 27 insertions, 18 deletions
diff --git a/chromium/third_party/blink/renderer/core/animation/keyframe_effect_model.h b/chromium/third_party/blink/renderer/core/animation/keyframe_effect_model.h
index 54224d18644..7ad2414d2cf 100644
--- a/chromium/third_party/blink/renderer/core/animation/keyframe_effect_model.h
+++ b/chromium/third_party/blink/renderer/core/animation/keyframe_effect_model.h
@@ -234,6 +234,12 @@ class KeyframeEffectModel final : public KeyframeEffectModelBase {
         keyframes, composite_, default_keyframe_easing_);
   }
 
+  KeyframeEffectModel<StringKeyframe>* CloneAsEmptyStringKeyframeModel() {
+    HeapVector<Member<StringKeyframe>> empty_keyframes;
+    return MakeGarbageCollected<KeyframeEffectModel<StringKeyframe>>(
+        empty_keyframes, composite_, default_keyframe_easing_);
+  }
+
  private:
   bool IsStringKeyframeEffectModel() const override { return false; }
   bool IsTransitionKeyframeEffectModel() const override { return false; }
@@ -253,35 +259,38 @@ using TransitionKeyframeVector = TransitionKeyframeEffectModel::KeyframeVector;
 using TransitionPropertySpecificKeyframeVector =
     TransitionKeyframeEffectModel::PropertySpecificKeyframeVector;
 
-DEFINE_TYPE_CASTS(KeyframeEffectModelBase,
-                  EffectModel,
-                  value,
-                  value->IsKeyframeEffectModel(),
-                  value.IsKeyframeEffectModel());
-DEFINE_TYPE_CASTS(StringKeyframeEffectModel,
-                  KeyframeEffectModelBase,
-                  value,
-                  value->IsStringKeyframeEffectModel(),
-                  value.IsStringKeyframeEffectModel());
-DEFINE_TYPE_CASTS(TransitionKeyframeEffectModel,
-                  KeyframeEffectModelBase,
-                  value,
-                  value->IsTransitionKeyframeEffectModel(),
-                  value.IsTransitionKeyframeEffectModel());
+template <>
+struct DowncastTraits<KeyframeEffectModelBase> {
+  static bool AllowFrom(const EffectModel& value) {
+    return value.IsKeyframeEffectModel();
+  }
+};
+template <>
+struct DowncastTraits<StringKeyframeEffectModel> {
+  static bool AllowFrom(const KeyframeEffectModelBase& value) {
+    return value.IsStringKeyframeEffectModel();
+  }
+};
+template <>
+struct DowncastTraits<TransitionKeyframeEffectModel> {
+  static bool AllowFrom(const KeyframeEffectModelBase& value) {
+    return value.IsTransitionKeyframeEffectModel();
+  }
+};
 
 inline const StringKeyframeEffectModel* ToStringKeyframeEffectModel(
     const EffectModel* base) {
-  return ToStringKeyframeEffectModel(ToKeyframeEffectModelBase(base));
+  return To<StringKeyframeEffectModel>(To<KeyframeEffectModelBase>(base));
 }
 
 inline StringKeyframeEffectModel* ToStringKeyframeEffectModel(
     EffectModel* base) {
-  return ToStringKeyframeEffectModel(ToKeyframeEffectModelBase(base));
+  return To<StringKeyframeEffectModel>(To<KeyframeEffectModelBase>(base));
 }
 
 inline TransitionKeyframeEffectModel* ToTransitionKeyframeEffectModel(
     EffectModel* base) {
-  return ToTransitionKeyframeEffectModel(ToKeyframeEffectModelBase(base));
+  return To<TransitionKeyframeEffectModel>(To<KeyframeEffectModelBase>(base));
 }
 
 template <>