Adding some logging for the test, testLaunchBlockedPopupInIncognito, to figure out its flakiness.

functional/popups.py

 #!/usr/bin/python
 
 # 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.
 
 import os
 
 import pyauto_functional  # Must be imported before pyauto
 import pyauto
@@ skipping 44 matching lines @@
     self.RunCommand(pyauto.IDC_NEW_INCOGNITO_WINDOW)
     file_url = self.GetFileURLForPath(os.path.join(
         self.DataDir(), 'popup_blocker', 'popup-window-open.html'))
     self.NavigateToURL(file_url, 1, 0)
     blocked_popups = self.GetBlockedPopupsInfo(tab_index=0, windex=1)
     self.assertEqual(1, len(blocked_popups), msg='Popup not blocked')
 
   def testLaunchBlockedPopupInIncognito(self):
     """Verify that a blocked popup can be unblocked in incognito."""
     self.RunCommand(pyauto.IDC_NEW_INCOGNITO_WINDOW)
+    self.assertTrue(2, self.GetBrowserWindowCount())
     file_url = self.GetFileURLForPath(os.path.join(
         self.DataDir(), 'popup_blocker', 'popup-window-open.html'))
     self.NavigateToURL(file_url, 1, 0)
+    self.assertEquals('Popup created using window.open',
+                      self.GetActiveTabTitle(window_index=1))
     # Wait until the popup is blocked
     self.assertTrue(self.WaitUntil(lambda:
         len(self.GetBlockedPopupsInfo(tab_index=0, windex=1)) is 1),
         msg='Popup not blocked')
     self.UnblockAndLaunchBlockedPopup(0, tab_index=0, windex=1)
     # Verify that no more popups are blocked
     self.assertFalse(self.GetBlockedPopupsInfo(tab_index=0, windex=1))
     # Verify that popup window was created
     self.assertEqual(3, self.GetBrowserWindowCount(),
                      msg='Popup could not be launched');
     self.assertEqual('Popup Success!', self.GetActiveTabTitle(2))
 
 
 if __name__ == '__main__':
   pyauto_functional.Main()