Oilpan: fix build after r175261.

Source/core/css/StylePropertySerializer.cpp

Index: Source/core/css/StylePropertySerializer.cpp
diff --git a/Source/core/css/StylePropertySerializer.cpp b/Source/core/css/StylePropertySerializer.cpp
index 4c8a63ff5b42ad15f0a8a33acff123fb990f6757..717bd84f0c7fa86e7a7204c990b219961bb02805 100644
--- a/Source/core/css/StylePropertySerializer.cpp
+++ b/Source/core/css/StylePropertySerializer.cpp
@@ -705,7 +705,7 @@ String StylePropertySerializer::borderPropertyValue(CommonValueMode valueMode) c
 static void appendBackgroundRepeatValue(StringBuilder& builder, const CSSValue& repeatXCSSValue, const CSSValue& repeatYCSSValue)
 {
     // FIXME: Ensure initial values do not appear in CSS_VALUE_LISTS.
-    DEFINE_STATIC_REF_WILL_BE_PERSISTENT(CSSPrimitiveValue, initialRepeatValue, CSSPrimitiveValue::create(CSSValueRepeat));
+    DEFINE_STATIC_REF_WILL_BE_PERSISTENT(CSSPrimitiveValue, initialRepeatValue, (CSSPrimitiveValue::create(CSSValueRepeat)));
     const CSSPrimitiveValue& repeatX = repeatXCSSValue.isInitialValue() ? *initialRepeatValue : toCSSPrimitiveValue(repeatXCSSValue);
     const CSSPrimitiveValue& repeatY = repeatYCSSValue.isInitialValue() ? *initialRepeatValue : toCSSPrimitiveValue(repeatYCSSValue);
     CSSValueID repeatXValueId = repeatX.getValueID();