[chromeos] Fix Logout automation when no browser windows are present.

chrome/test/functional/chromeos_login.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 import os
 import subprocess
 import sys
 
 import pyauto_functional  # Must be imported before pyauto
@@ skipping 138 matching lines @@
     This test is to verify the stability of the automation interface.
 
     """
     self.testGoodLogin()
     self.Logout()
     self.testBadPassword()
     self.testLoginAsGuest()
     self.Logout()
     self.testLoginToCreateNewAccount()
 
+  def testLogoutWithNoWindows(self):
+    """Verify logout when no browser windows are present."""
+    self.testGoodLogin()
+    for i in range(5):
+      self.OpenNewBrowserWindow(True)
+    for _ in range(self.GetBrowserWindowCount()):
+      self.CloseBrowserWindow(0)
+    self.assertEqual(0, self.GetBrowserWindowCount(),
+                     msg='Could not close all browser windows')
+    self.Logout()
+    self.testGoodLogin()
+
 
 if __name__ == '__main__':
   pyauto_functional.Main()