Oilpan: make shutdown of plugin container objects work better.

Source/web/WebPluginContainerImpl.h

Index: Source/web/WebPluginContainerImpl.h
diff --git a/Source/web/WebPluginContainerImpl.h b/Source/web/WebPluginContainerImpl.h
index 46728ee49c15c26f3ee90f5d85531522531f6e4b..d5dfe214ee92082dc0d8f6e0cb19eca2863a92ed 100644
--- a/Source/web/WebPluginContainerImpl.h
+++ b/Source/web/WebPluginContainerImpl.h
@@ -51,6 +51,9 @@ class MouseEvent;
 class PlatformGestureEvent;
 class ResourceError;
 class ResourceResponse;
+#if ENABLE(OILPAN)
+class ScriptController;
+#endif
 class TouchEvent;
 class WheelEvent;
 class Widget;
@@ -162,6 +165,11 @@ public:
 
     bool paintCustomOverhangArea(WebCore::GraphicsContext*, const WebCore::IntRect&, const WebCore::IntRect&, const WebCore::IntRect&);
 
+#if ENABLE(OILPAN)
+    virtual void detach() OVERRIDE;
+    virtual void setScriptController(WebCore::ScriptController*) OVERRIDE;
+#endif
+
 private:
     WebPluginContainerImpl(WebCore::HTMLPlugInElement* element, WebPlugin* webPlugin);
     virtual ~WebPluginContainerImpl();
@@ -185,10 +193,19 @@ private:
     void windowCutOutRects(const WebCore::IntRect& frameRect,
                            Vector<WebCore::IntRect>& cutOutRects);
 
+    // FIXME: Oilpan: consider moving Widget to the heap and turn this
+    // into a traced member. For the time being, it is a bare pointer
+    // of its owning PlugInElement and managed as such.
     WebCore::HTMLPlugInElement* m_element;
     WebPlugin* m_webPlugin;
     Vector<WebPluginLoadObserver*> m_pluginLoadObservers;
 
+#if ENABLE(OILPAN)
+    // Keep a direct reference to the object we've registered with.
+    // Needed for reliable finalization.
+    WebCore::ScriptController* m_scriptController;
+#endif
+
     WebLayer* m_webLayer;
 
     // The associated scrollbar group object, created lazily. Used for Pepper