Oilpan: Support nested pre-finalizers

Source/core/frame/LocalDOMWindow.h

Index: Source/core/frame/LocalDOMWindow.h
diff --git a/Source/core/frame/LocalDOMWindow.h b/Source/core/frame/LocalDOMWindow.h
index 3ff528dfbbfee44bb093fbaf8efe2d92f913f3f3..a70b099f920e417a347ab31f1b86addbc11b1929 100644
--- a/Source/core/frame/LocalDOMWindow.h
+++ b/Source/core/frame/LocalDOMWindow.h
@@ -75,7 +75,6 @@ public:
     }
 
     virtual ~LocalDOMWindow();
-    void dispose();
 
     DECLARE_VIRTUAL_TRACE();
 
@@ -234,6 +233,7 @@ private:
     friend WTF::OwnedPtrDeleter<WindowFrameObserver>;
 
     explicit LocalDOMWindow(LocalFrame&);
+    void dispose();
 
     Page* page();