Move the Widget hierarchy to the Oilpan heap.

Source/bindings/core/v8/ScriptController.h

Index: Source/bindings/core/v8/ScriptController.h
diff --git a/Source/bindings/core/v8/ScriptController.h b/Source/bindings/core/v8/ScriptController.h
index c16bf4bc095b12991e1630ce8d69702ca2f056cc..28ce8960761727b94d8efb7e36bea3fcf5c98f64 100644
--- a/Source/bindings/core/v8/ScriptController.h
+++ b/Source/bindings/core/v8/ScriptController.h
@@ -73,7 +73,11 @@ public:
         DoNotExecuteScriptWhenScriptsDisabled
     };
 
-    ScriptController(LocalFrame*);
+    static PassOwnPtr<ScriptController> create(LocalFrame* frame)
+    {
+        return adoptPtr(new ScriptController(frame));
+    }
+
     ~ScriptController();
 
     bool initializeMainWorld();
@@ -133,7 +137,6 @@ public:
     void updateSecurityOrigin(SecurityOrigin*);
     void clearScriptObjects();
     void cleanupScriptObjectsForPlugin(Widget*);
-
     void clearForClose();
 
     NPObject* createScriptObjectForPluginElement(HTMLPlugInElement*);
@@ -150,6 +153,8 @@ public:
     v8::Isolate* isolate() const { return m_isolate; }
 
 private:
+    explicit ScriptController(LocalFrame*);
+
     typedef HashMap<int, OwnPtr<WindowProxy> > IsolatedWorldMap;
     typedef HashMap<Widget*, NPObject*> PluginObjectMap;