WIP Support var() references in registered custom property keyframes

third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h

Index: third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h
diff --git a/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h b/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h
index dbb8a821b4ad55e9ab8b9e77311b7046b72848a8..bf4d02803a7950fff5611c9f27e7f16a710beffd 100644
--- a/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h
+++ b/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.h
@@ -13,10 +13,12 @@
 
 namespace blink {
 
+class CSSCustomPropertyDeclaration;
 class CSSParserTokenRange;
 class CSSPendingSubstitutionValue;
 class CSSVariableData;
 class CSSVariableReferenceValue;
+class PropertyRegistration;
 class PropertyRegistry;
 class StyleResolverState;
 class StyleInheritedVariables;
@@ -28,6 +30,10 @@ class CSSVariableResolver {
  public:
   CSSVariableResolver(const StyleResolverState&);
 
+  const CSSValue* ResolveRegisteredCustomPropertyAnimationKeyframe(
+      const PropertyRegistration&,
+      const CSSCustomPropertyDeclaration& keyframe);
+
   void ResolveVariableDefinitions();
 
   // Shorthand properties are not supported.