Always turn on auto-updating on firefox for browser tests.

tools/testing/run_selenium.py

 #!/usr/bin/python
 
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 
 """Script to actually open a browser and perform the test, and reports back with
 the result. It uses Selenium WebDriver when possible for running the tests. It
 uses Selenium RC for Safari.
@@ skipping 149 matching lines @@
     elif platform.system() == 'Darwin':
       options.binary_location = os.path.join(dartium_dir, 'Chromium.app',
                                              'Contents', 'MacOS', 'Chromium')
     else:
       options.binary_location = os.path.join(dartium_dir, 'chrome')
     return selenium.webdriver.Chrome(chrome_options=options)
   elif browser == 'ff':
     profile = selenium.webdriver.firefox.firefox_profile.FirefoxProfile()
     profile.set_preference('dom.max_script_run_time', 0)
     profile.set_preference('dom.max_chrome_script_run_time', 0)
+    profile.set_preference('app.update.auto', True)
+    profile.set_preference('app.update.enabled', True)
     return selenium.webdriver.Firefox(firefox_profile=profile)
   elif browser == 'ie' and platform.system() == 'Windows':
     return selenium.webdriver.Ie()
   elif browser == 'safari' and platform.system() == 'Darwin':
     # TODO(efortuna): Ensure our preferences (no pop-up blocking) file is the
     # same (Safari auto-deletes when it has too many "crashes," or in our case,
     # timeouts). Come up with a less hacky way to do this.
     backup_safari_prefs = os.path.dirname(__file__) + '/com.apple.Safari.plist'
     if os.path.exists(backup_safari_prefs):
       shutil.copy(backup_safari_prefs,
@@ skipping 147 matching lines @@
   browser = start_browser(browser_name, executable_path, html_out)
 
   try:
     output = run_test_in_browser(browser, html_out, timeout, mode)
     return report_results(mode, output)
   finally:
     close_browser(browser)
 
 if __name__ == "__main__":
   sys.exit(main(sys.argv))