Split out Attribute from CSSPrimitiveValue

Source/core/css/CSSCalculationValue.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 105 matching lines @@
     case CSSPrimitiveValue::UnitType::DotsPerPixel:
     case CSSPrimitiveValue::UnitType::DotsPerInch:
     case CSSPrimitiveValue::UnitType::DotsPerCentimeter:
     case CSSPrimitiveValue::UnitType::Fraction:
     case CSSPrimitiveValue::UnitType::Integer:
         return true;
     case CSSPrimitiveValue::UnitType::Unknown:
     case CSSPrimitiveValue::UnitType::CustomIdentifier:
     case CSSPrimitiveValue::UnitType::String:
     case CSSPrimitiveValue::UnitType::URI:
-    case CSSPrimitiveValue::UnitType::Attribute:
     case CSSPrimitiveValue::UnitType::RGBColor:
     case CSSPrimitiveValue::UnitType::Shape:
     case CSSPrimitiveValue::UnitType::Calc:
     case CSSPrimitiveValue::UnitType::CalcPercentageWithNumber:
     case CSSPrimitiveValue::UnitType::CalcPercentageWithLength:
     case CSSPrimitiveValue::UnitType::PropertyID:
     case CSSPrimitiveValue::UnitType::ValueID:
     case CSSPrimitiveValue::UnitType::QuirkyEms:
         return false;
     };
@@ skipping 605 matching lines @@
 
     return expression ? adoptRefWillBeNoop(new CSSCalcValue(expression, range)) : nullptr;
 }
 
 PassRefPtrWillBeRawPtr<CSSCalcValue> CSSCalcValue::create(PassRefPtrWillBeRawPtr<CSSCalcExpressionNode> expression, ValueRange range)
 {
     return adoptRefWillBeNoop(new CSSCalcValue(expression, range));
 }
 
 } // namespace blink