Remove CSSParserValue::createCSSValue and unused callers

Source/core/css/parser/CSSParserValues.h

Index: Source/core/css/parser/CSSParserValues.h
diff --git a/Source/core/css/parser/CSSParserValues.h b/Source/core/css/parser/CSSParserValues.h
index 3ec2081ca00a1f70581cef40cd18852a85debb35..07c5df807c492c09ee502da76a5f73b36a261ed4 100644
--- a/Source/core/css/parser/CSSParserValues.h
+++ b/Source/core/css/parser/CSSParserValues.h
@@ -136,6 +136,7 @@ template <>
 inline const UChar* CSSParserString::characters<UChar>() const { return characters16(); }
 
 struct CSSParserFunction;
+class CSSParserValueList;
 
 struct CSSParserValue {
     CSSValueID id;
@@ -158,8 +159,6 @@ struct CSSParserValue {
     inline void setFromNumber(double value, int unit = CSSPrimitiveValue::CSS_NUMBER);
     inline void setFromFunction(CSSParserFunction*);
     inline void setFromValueList(PassOwnPtr<CSSParserValueList>);
-
-    PassRefPtrWillBeRawPtr<CSSValue> createCSSValue();
 };
 
 class CSSParserValueList {