Introduce a field trial for Instant.

chrome/test/functional/instant.py

 #!/usr/bin/python
 
 # Copyright (c) 2011 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 cgi
 import os
 
 import pyauto_functional  # Must be imported before pyauto
 import pyauto
 
 
 class InstantSettingsTest(pyauto.PyUITest):
   """Test Chrome Instant settings."""
 
   def testEnableDisableInstant(self):
     """Test to verify default Chrome Instant setting.
     Check if the setting can be enabled and disabled."""
     self.assertFalse(self.GetPrefsInfo().Prefs(pyauto.kInstantEnabled),
                      msg='Instant is enabled by default.')
     # Enable instant.
     self.SetPrefs(pyauto.kInstantEnabled, True)
+    self.SetPrefs(pyauto.kInstantEnabledOnce, True)
     self.assertTrue(self.GetPrefsInfo().Prefs(pyauto.kInstantEnabled),
                     msg='Instant is not enabled.')
     self.SetOmniboxText('google.com')
     self.assertTrue(self.WaitUntil(
         lambda: self.GetInstantInfo().get('current') and not
         self.GetInstantInfo().get('loading')))
     title = self.GetInstantInfo()['title']
     self.assertEqual('Google', title, msg='Instant did not load.')
     # Disable Instant.
     self.SetPrefs(pyauto.kInstantEnabled, False)
@@ skipping 231 matching lines @@
     """Test that instant loads PNG file."""
     self._AssertInstantLoadsFile(os.path.join('save_page', '1.png'))
 
   def testInstantLoadsSVG(self):
     """Test that instant loads SVG file."""
     self._AssertInstantLoadsFile(os.path.join('circle.svg'))
 
 
 if __name__ == '__main__':
   pyauto_functional.Main()