Make maybeConvertNeutral pure virtual

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

Index: third_party/WebKit/Source/core/animation/SVGTransformListInterpolationType.cpp
diff --git a/third_party/WebKit/Source/core/animation/SVGTransformListInterpolationType.cpp b/third_party/WebKit/Source/core/animation/SVGTransformListInterpolationType.cpp
index 935d9636d1db132b5f8ed72d068c4dc4d168a45c..f195fb0bfe4fed8915935f9bc8105ea8227cb95e 100644
--- a/third_party/WebKit/Source/core/animation/SVGTransformListInterpolationType.cpp
+++ b/third_party/WebKit/Source/core/animation/SVGTransformListInterpolationType.cpp
@@ -210,6 +210,13 @@ private:
 
 } // namespace
 
+InterpolationValue SVGTransformListInterpolationType::maybeConvertNeutral(const InterpolationValue&, ConversionCheckers&) const
+{
+    NOTREACHED();
+    // This function is no longer called, because maybeConvertSingle has been overridden.
+    return nullptr;
+}
+
 InterpolationValue SVGTransformListInterpolationType::maybeConvertSVGValue(const SVGPropertyBase& svgValue) const
 {
     if (svgValue.type() != AnimatedTransformList)