Oilpan: make shutdown of plugin container objects work better.

Source/platform/Widget.h

Index: Source/platform/Widget.h
diff --git a/Source/platform/Widget.h b/Source/platform/Widget.h
index 4b042fc06ef12b3acef6f99f45ed32dd08b8c3c5..ae57ae7c8f0fbe800a87fb990f2f09e62960fa88 100644
--- a/Source/platform/Widget.h
+++ b/Source/platform/Widget.h
@@ -39,6 +39,9 @@ namespace WebCore {
 class Event;
 class GraphicsContext;
 class HostWindow;
+#if ENABLE(OILPAN)

[tkent, 2014/06/25 05:05:40]

nit: You don't need to add |#if ENABLE(OILPAN)| to class declarations. It
doesn't affect generated code of enable_oilpan=0.

+class ScriptController;
+#endif
 
 // The Widget class serves as a base class for three kinds of objects:
 // (1) Scrollable areas (ScrollView)
@@ -133,6 +136,12 @@ public:
     // Notifies this widget that it will no longer be receiving events.
     virtual void eventListenersRemoved() { }
 
+#if ENABLE(OILPAN)
+    virtual void detach() { }
+
+    virtual void setScriptController(ScriptController*) { }
+#endif
+
 private:
     Widget* m_parent;
     IntRect m_frame;