CSSValue Immediates: Replace CSSValue usage with const references

Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp

Index: Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
diff --git a/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp b/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
index 7bebd274db97ad94be1f1dd276b8a4a9c61afded..75dac62fd9f8e3e3e26c21f1f535358ff5770f61 100644
--- a/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
+++ b/Source/bindings/core/v8/custom/V8CSSStyleDeclarationCustom.cpp
@@ -203,7 +203,7 @@ void V8CSSStyleDeclaration::namedPropertyGetterCustom(v8::Local<v8::Name> name,
     CSSPropertyID resolvedProperty = resolveCSSPropertyID(unresolvedProperty);
 
     CSSStyleDeclaration* impl = V8CSSStyleDeclaration::toImpl(info.Holder());
-    NullableCSSValue cssValue = impl->getPropertyCSSValueInternal(resolvedProperty);
+    const NullableCSSValue& cssValue = impl->getPropertyCSSValueInternal(resolvedProperty);
     if (cssValue) {
         v8SetReturnValueStringOrNull(info, cssValue->cssText(), info.GetIsolate());
         return;