Add simple update test to pfq.

bin/cros_au_test_harness.py

 #!/usr/bin/python
 
 # Copyright (c) 2011 The Chromium OS 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 optparse
 import os
 import re
 import sys
@@ skipping 360 matching lines @@
 
     self.AttemptUpdateWithFilter(DelayedFilter())
 
   def SimpleTest(self):
     """A simple update  that updates the target image to itself.
 
     We explicitly don't use test prefix so that isn't run by default.  Can be
     run using test_prefix option.
     """
     self.PrepareBase(self.target_image_path)
-    self._UpdateImage(self.target_image_path)
+    self.PerformUpdate(self.target_image_path, self.target_image_path)
     self.VerifyImage(100)
 
 
 class RealAUTest(unittest.TestCase, AUTest):
   """Test harness for updating real images."""
 
   def setUp(self):
     AUTest.setUp(self)
 
   @classmethod
@@ skipping 246 matching lines @@
   test_loader.testMethodPrefix = options.test_prefix
   test_suite = test_loader.loadTestsFromTestCase(test_class)
   test_result = unittest.TextTestRunner(verbosity=2).run(test_suite)
 
   if not test_result.wasSuccessful():
     Die('Test harness was not successful')
 
 
 if __name__ == '__main__':
   main()