CSSValue Immediates: Replace CSSValue usage with const references

Source/core/page/PageSerializer.cpp

Index: Source/core/page/PageSerializer.cpp
diff --git a/Source/core/page/PageSerializer.cpp b/Source/core/page/PageSerializer.cpp
index 96cf7eeb3edea9935bcf8bfcac2c007e08e4c950..0ba2049bb320a0cb52a6db144312b3ed53ba4da4 100644
--- a/Source/core/page/PageSerializer.cpp
+++ b/Source/core/page/PageSerializer.cpp
@@ -521,12 +521,12 @@ void PageSerializer::retrieveResourcesForProperties(const StylePropertySet* styl
     // image properties there might be.
     unsigned propertyCount = styleDeclaration->propertyCount();
     for (unsigned i = 0; i < propertyCount; ++i) {
-        CSSValue cssValue = styleDeclaration->propertyAt(i).value();
+        const CSSValue& cssValue = styleDeclaration->propertyAt(i).value();
         retrieveResourcesForCSSValue(cssValue, document);
     }
 }
 
-void PageSerializer::retrieveResourcesForCSSValue(CSSValue cssValue, Document& document)
+void PageSerializer::retrieveResourcesForCSSValue(const CSSValue& cssValue, Document& document)
 {
     if (cssValue.isImageValue()) {
         CSSImageValue& imageValue = toCSSImageValue(cssValue);