Make CSSInterpolationType::maybeConvertSingle() final

third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp

Index: third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp
diff --git a/third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp b/third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp
index 7753731ef05eacdb9e26303452f841783c392395..79095cd4b075eff47396d0b236b6312066d963fe 100644
--- a/third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp
+++ b/third_party/WebKit/Source/core/animation/CSSRotateInterpolationType.cpp
@@ -161,19 +161,10 @@ InterpolationValue CSSRotateInterpolationType::maybeConvertValue(
   return convertRotation(StyleBuilderConverter::convertRotation(value));
 }
 
-InterpolationValue CSSRotateInterpolationType::maybeConvertSingle(
-    const PropertySpecificKeyframe& keyframe,
-    const InterpolationEnvironment& environment,
-    const InterpolationValue& underlying,
-    ConversionCheckers& conversionCheckers) const {
-  InterpolationValue result = CSSInterpolationType::maybeConvertSingle(
-      keyframe, environment, underlying, conversionCheckers);
-  if (!result)
-    return nullptr;
-  if (keyframe.composite() != EffectModel::CompositeReplace)
-    toCSSRotateNonInterpolableValue(*result.nonInterpolableValue)
-        .setSingleAdditive();
-  return result;
+void CSSRotateInterpolationType::additiveKeyframeHook(
+    InterpolationValue& value) const {
+  toCSSRotateNonInterpolableValue(*value.nonInterpolableValue)
+      .setSingleAdditive();
 }
 
 PairwiseInterpolationValue CSSRotateInterpolationType::maybeMergeSingles(