CSSValue Immediates: Replace CSSValue usage with const references

Source/core/css/StylePropertySet.cpp

Index: Source/core/css/StylePropertySet.cpp
diff --git a/Source/core/css/StylePropertySet.cpp b/Source/core/css/StylePropertySet.cpp
index 4faea219044b1a2edac335dcdd63184cc360f449..11b599a6d725e5e4179937ff7c6b341ce750636b 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -250,7 +250,7 @@ bool MutableStylePropertySet::setProperty(CSSPropertyID unresolvedProperty, cons
     return CSSParser::parseValue(this, unresolvedProperty, value, important, cssParserMode(), contextStyleSheet);
 }
 
-void MutableStylePropertySet::setProperty(CSSPropertyID propertyID, CSSValue prpValue, bool important)
+void MutableStylePropertySet::setProperty(CSSPropertyID propertyID, const CSSValue& prpValue, bool important)
 {
     StylePropertyShorthand shorthand = shorthandForProperty(propertyID);
     if (!shorthand.length()) {
@@ -260,7 +260,7 @@ void MutableStylePropertySet::setProperty(CSSPropertyID propertyID, CSSValue prp
 
     removePropertiesInSet(shorthand.properties(), shorthand.length());
 
-    CSSValue value = prpValue;
+    const CSSValue& value = prpValue;
     for (unsigned i = 0; i < shorthand.length(); ++i)
         m_propertyVector.append(CSSProperty(shorthand.properties()[i], value, important));
 }
@@ -388,7 +388,7 @@ CSSProperty* MutableStylePropertySet::findCSSPropertyWithID(CSSPropertyID proper
     return &m_propertyVector.at(foundPropertyIndex);
 }
 
-bool StylePropertySet::propertyMatches(CSSPropertyID propertyID, const CSSValue propertyValue) const
+bool StylePropertySet::propertyMatches(CSSPropertyID propertyID, const CSSValue& propertyValue) const
 {
     int foundPropertyIndex = findPropertyIndex(propertyID);
     if (foundPropertyIndex == -1)