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

chrome/browser/automation/automation_provider_win.cc

 // Copyright (c) 2009 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.
 
 #include "chrome/browser/automation/automation_provider.h"
 
 #include "base/json/json_reader.h"
 #include "base/keyboard_codes.h"
 #include "chrome/browser/automation/automation_extension_function.h"
 #include "chrome/browser/automation/extension_automation_constants.h"
@@ skipping 572 matching lines @@
     int handle, int navigation_index,
     AutomationMsg_NavigationResponseValues* status) {
   *status = AUTOMATION_MSG_NAVIGATION_ERROR;
 
   if (tab_tracker_->ContainsHandle(handle)) {
     NavigationController* tab = tab_tracker_->GetResource(handle);
     tab->GoToIndex(navigation_index);
     *status = AUTOMATION_MSG_NAVIGATION_SUCCESS;
   }
 }
+
+void AutomationProvider::OnRunUnloadHandlers(
+    int handle, gfx::NativeWindow notification_window,
+    int notification_message) {
+  ExternalTabContainer* external_tab = GetExternalTabForHandle(handle);
+  if (external_tab) {
+    external_tab->RunUnloadHandlers(notification_window, notification_message);
+  }
+}
+