Ensure proper finalization of garbage-collected types.

Source/core/css/CSSBasicShapes.h

Index: Source/core/css/CSSBasicShapes.h
diff --git a/Source/core/css/CSSBasicShapes.h b/Source/core/css/CSSBasicShapes.h
index 78b84df13d793817ce10a33bcdce42719be87afb..fa6ce08717e1dedbd3b307f3c12342eb028233bb 100644
--- a/Source/core/css/CSSBasicShapes.h
+++ b/Source/core/css/CSSBasicShapes.h
@@ -39,6 +39,7 @@
 namespace WebCore {
 
 class CSSBasicShape : public RefCountedWillBeGarbageCollected<CSSBasicShape> {
+    DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CSSBasicShape);
 public:
     enum Type {
         CSSBasicShapeRectangleType,
@@ -60,9 +61,6 @@ public:
 
     virtual void trace(Visitor* visitor) { visitor->trace(m_layoutBox); }
 
-public:
-    virtual ~CSSBasicShape() { }
-
 protected:
     CSSBasicShape() { }
     RefPtrWillBeMember<CSSPrimitiveValue> m_layoutBox;