Speculative fix for build on windows build bots.

recipes/ios.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.
 
 import sys
 
 import recipe_util  # pylint: disable=F0401
 
 
 # This class doesn't need an __init__ method, so we disable the warning
 # pylint: disable=W0232
 class IOS(recipe_util.Recipe):
   """Basic Recipe alias for iOS -> Chromium."""
 
   @staticmethod
   def fetch_spec(props):
     return {
       'alias': {
         'recipe': 'chromium',
         'props': ['--target_os=ios', '--target_os_only=True'],
       },
     }
 
+  @staticmethod
+  def expected_root(_props):
+    return ''
+
 
 def main(argv=None):
   return IOS().handle_args(argv)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))