CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/css/parser/CSSParser.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/css/parser/CSSParser.h"
 
 #include "core/css/CSSKeyframeRule.h"
 #include "core/css/StyleColor.h"
 #include "core/css/StylePropertySet.h"
@@ skipping 110 matching lines @@
     }
 
     NullableCSSValue value = CSSParserFastPaths::parseColor(string, !strict);
     // TODO(timloh): Why is this always strict mode?
     if (!value)
         value = parseSingleValue(CSSPropertyColor, string, strictCSSParserContext());
 
     if (!value || !value->isPrimitiveValue())
         return false;
 
-    CSSPrimitiveValue primitiveValue = toCSSPrimitiveValue(*value);
+    const CSSPrimitiveValue& primitiveValue = toCSSPrimitiveValue(value);
     if (!primitiveValue.isRGBColor())
         return false;
 
     color = primitiveValue.getRGBA32Value();
     return true;
 }
 
 StyleColor CSSParser::colorFromRGBColorString(const String& string)
 {
     // FIXME: Rework css parser so it is more SVG aware.
@@ skipping 25 matching lines @@
     builder.appendLiteral(" : ");
     builder.append(propertyValue);
     builder.appendLiteral("; }");
     RefPtrWillBeRawPtr<StyleRuleBase> rule = parseRule(context, nullptr, builder.toString());
     if (!rule || !rule->isFontFaceRule())
         return nullptr;
     return toStyleRuleFontFace(rule.get())->properties().getPropertyCSSValue(propertyID);
 }
 
 } // namespace blink