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

chrome_frame/chrome_frame_automation.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.
 
 #ifndef CHROME_FRAME_CHROME_FRAME_AUTOMATION_H_
 #define CHROME_FRAME_CHROME_FRAME_AUTOMATION_H_
 
 #include <atlbase.h>
 #include <atlwin.h>
 #include <string>
@@ skipping 255 matching lines @@
 
   // Attaches an existing external tab to this automation client instance.
   void AttachExternalTab(uint64 external_tab_cookie);
   void BlockExternalTab(uint64 cookie);
 
   void SetPageFontSize(enum AutomationPageFontSize);
 
   // For IDeleteBrowsingHistorySupport
   void RemoveBrowsingData(int remove_mask);
 
+  // Sends an IPC message to the external tab container requesting it to run
+  // unload handlers on the page.
+  void RunUnloadHandlers(HWND notification_window, int notification_message);
+
  protected:
   // ChromeFrameAutomationProxy::LaunchDelegate implementation.
   virtual void LaunchComplete(ChromeFrameAutomationProxy* proxy,
                             AutomationLaunchResult result);
   // TabProxyDelegate implementation
   virtual void OnMessageReceived(TabProxy* tab, const IPC::Message& msg);
   virtual void OnChannelError(TabProxy* tab);
 
   void CreateExternalTab();
   AutomationLaunchResult CreateExternalTabComplete(HWND chrome_window,
@@ skipping 86 matching lines @@
  public:
   void SetUrlFetcher(PluginUrlRequestManager* url_fetcher) {
     DCHECK(url_fetcher != NULL);
     url_fetcher_ = url_fetcher;
     url_fetcher_flags_ = url_fetcher->GetThreadSafeFlags();
     url_fetcher_->set_delegate(this);
   }
 };
 
 #endif  // CHROME_FRAME_CHROME_FRAME_AUTOMATION_H_