CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/css/CSSShadowValue.cpp

 /**
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 #include "config.h"
 #include "core/css/CSSShadowValue.h"
 
 #include "core/css/CSSPrimitiveValue.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 // Used for text-shadow and box-shadow
-CSSShadowValue::CSSShadowValue(NullableCSSValue x,
-    NullableCSSValue y,
-    NullableCSSValue blur,
-    NullableCSSValue spread,
-    NullableCSSValue style,
-    NullableCSSValue color)
+CSSShadowValue::CSSShadowValue(const NullableCSSValue& x,
+    const NullableCSSValue& y,
+    const NullableCSSValue& blur,
+    const NullableCSSValue& spread,
+    const NullableCSSValue& style,
+    const NullableCSSValue& color)
     : CSSValueObject(ShadowClass)
     , x(x)
     , y(y)
     , blur(blur)
     , spread(spread)
     , style(style)
     , color(color)
 {
 }
 
@@ skipping 47 matching lines @@
     visitor->trace(x);
     visitor->trace(y);
     visitor->trace(blur);
     visitor->trace(spread);
     visitor->trace(style);
     visitor->trace(color);
     CSSValueObject::traceAfterDispatch(visitor);
 }
 
 }