CSSValue Immediates: Make CSSPrimitiveValue a container

Source/core/css/resolver/StyleBuilderConverter.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * 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
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 107 matching lines @@
     if (value.isPrimitiveValue() && toCSSPrimitiveValue(value).getValueID() == CSSValueNone)
         return flags;
     for (auto& flagValue : toCSSValueList(value))
         flags |= toCSSPrimitiveValue(flagValue);
     return flags;
 }
 
 template <typename T>
 T StyleBuilderConverter::convertLineWidth(StyleResolverState& state, CSSValue value)
 {
-    CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
+    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
     CSSValueID valueID = primitiveValue.getValueID();
     if (valueID == CSSValueThin)
         return 1;
     if (valueID == CSSValueMedium)
         return 3;
     if (valueID == CSSValueThick)
         return 5;
     if (valueID == CSSValueInvalid) {
         // Any original result that was >= 1 should not be allowed to fall below 1.
         // This keeps border lines from vanishing.
         T result = primitiveValue.computeLength<T>(state.cssToLengthConversionData());
         if (state.style()->effectiveZoom() < 1.0f && result < 1.0) {
             T originalLength = primitiveValue.computeLength<T>(state.cssToLengthConversionData().copyWithAdjustedZoom(1.0));
             if (originalLength >= 1.0)
                 return 1.0;
         }
         return result;
     }
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 template <CSSValueID IdForNone>
 AtomicString StyleBuilderConverter::convertString(StyleResolverState&, CSSValue value)
 {
-    CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
+    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue.getValueID() == IdForNone)
         return nullAtom;
     return AtomicString(primitiveValue.getStringValue());
 }
 
 } // namespace blink
 
 #endif