WIP Support var() references in registered custom property keyframes

third_party/WebKit/Source/core/animation/CSSInterpolationType.h

Index: third_party/WebKit/Source/core/animation/CSSInterpolationType.h
diff --git a/third_party/WebKit/Source/core/animation/CSSInterpolationType.h b/third_party/WebKit/Source/core/animation/CSSInterpolationType.h
index c2eb7df21b6cd4ef4622236c585585d50907836b..55bc34ac609af7f79653797c3bc794a43c2bcfbf 100644
--- a/third_party/WebKit/Source/core/animation/CSSInterpolationType.h
+++ b/third_party/WebKit/Source/core/animation/CSSInterpolationType.h
@@ -11,6 +11,7 @@
 namespace blink {
 
 class CSSCustomPropertyDeclaration;
+class CSSVariableResolver;
 class ComputedStyle;
 class PropertyRegistration;
 class StyleResolverState;
@@ -75,10 +76,12 @@ class CSSInterpolationType : public InterpolationType {
   InterpolationValue MaybeConvertCustomPropertyDeclaration(
       const CSSCustomPropertyDeclaration&,
       const StyleResolverState&,
+      CSSVariableResolver&,
       ConversionCheckers&) const;
   InterpolationValue MaybeConvertCustomPropertyDeclarationInternal(
       const CSSCustomPropertyDeclaration&,
       const StyleResolverState&,
+      CSSVariableResolver&,
       ConversionCheckers&) const;
 
   virtual const CSSValue* CreateCSSValue(const InterpolableValue&,