ChromeFrame tabs would hang at times while closing. This would randomly occur...

chrome/browser/automation/automation_provider.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This implements a browser-side endpoint for UI automation activity.
 // The client-side endpoint is implemented by AutomationProxy.
 // The entire lifetime of this object should be contained within that of
 // the BrowserProcess, and in particular the NotificationService that's
 // hung off of it.
 
@@ skipping 811 matching lines @@
                                  const std::string& target);
 
   // Determine if the message from the external host represents a browser
   // event, and if so dispatch it.
   bool InterceptBrowserEventMessageFromExternalHost(const std::string& message,
                                                     const std::string& origin,
                                                     const std::string& target);
 
   void OnBrowserMoved(int handle);
 
+  void OnRunUnloadHandlers(int handle, gfx::NativeWindow notification_window,
+                           int notification_message);
+
   ExternalTabContainer* GetExternalTabForHandle(int handle);
 #endif  // defined(OS_WIN)
 
   typedef ObserverList<NotificationObserver> NotificationObserverList;
   typedef std::map<NavigationController*, LoginHandler*> LoginHandlerMap;
   typedef std::map<int, ExtensionPortContainer*> PortContainerMap;
 
   scoped_ptr<IPC::ChannelProxy> channel_;
   scoped_ptr<InitialLoadObserver> initial_load_observer_;
   scoped_ptr<NotificationObserver> new_tab_ui_load_observer_;
@@ skipping 65 matching lines @@
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
   void OnRemoveProvider();  // Called via PostTask
 
   NotificationRegistrar registrar_;
 };
 
 #endif  // CHROME_BROWSER_AUTOMATION_AUTOMATION_PROVIDER_H_