CSSValue Immediates: Replace CSSValue usage with const references

Source/core/css/StylePropertySerializer.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Research In Motion Limited. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. All rights reserved.
  *
  * 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.
@@ skipping 47 matching lines @@
     // Only StylePropertySerializer uses the following two classes.
     class PropertyValueForSerializer {
     public:
         explicit PropertyValueForSerializer(StylePropertySet::PropertyReference property)
             : m_value(property.value())
             , m_id(property.id())
             , m_isImportant(property.isImportant())
             , m_isImplicit(property.isImplicit())
             , m_isInherited(property.isInherited()) { }
 
-        PropertyValueForSerializer(CSSPropertyID id, const CSSValue value, bool isImportant)
+        PropertyValueForSerializer(CSSPropertyID id, const CSSValue& value, bool isImportant)
             : m_value(value)
             , m_id(id)
             , m_isImportant(isImportant)
             , m_isImplicit(value.isImplicitInitialValue())
             , m_isInherited(value.isInheritedValue()) { }
 
         CSSPropertyID id() const { return m_id; }
-        const CSSValue value() const { return m_value; }
+        const CSSValue& value() const { return m_value; }
         bool isImportant() const { return m_isImportant; }
         bool isImplicit() const { return m_isImplicit; }
         bool isInherited() const { return m_isInherited; }
 
         DEFINE_INLINE_TRACE()
         {
             visitor->trace(m_value);
         }
     private:
         const CSSValue m_value;
@@ skipping 25 matching lines @@
         BitArray<numCSSProperties> m_longhandPropertyUsed;
         bool m_needToExpandAll;
     };
 
     const StylePropertySetForSerializer m_propertySet;
 };
 
 } // namespace blink
 
 #endif