Uninstall Chrome silently in the mini_installer test framework.

chrome/test/mini_installer/uninstall_chrome.py

 # Copyright 2013 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.
 
 """Uninstalls Chrome.
 
 This script reads the uninstall command from registry, calls it, and verifies
 the output status code.
 """
 
@@ skipping 20 matching lines @@
   sub_key = ('SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\%s' %
              options.chrome_long_name)
   # Query the key. It will throw a WindowsError if the key doesn't exist.
   try:
     key = _winreg.OpenKey(root_key, sub_key, 0, _winreg.KEY_QUERY_VALUE)
   except WindowsError:
     raise KeyError('Registry key %s\\%s is missing' % (
         'HKEY_LOCAL_MACHINE' if options.system_level else 'HKEY_CURRENT_USER',
         sub_key))
   uninstall_string, _ = _winreg.QueryValueEx(key, 'UninstallString')
-  exit_status = subprocess.call(uninstall_string, shell=True)
+  exit_status = subprocess.call(uninstall_string + ' --force-uninstall',
+                                shell=True)
   # The exit status for successful uninstallation of Chrome is 19 (see
   # chrome/installer/util/util_constants.h).
   if exit_status != 19:
     raise Exception('Could not uninstall Chrome. The installer exited with '
                     'status %d.' % exit_status)
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())