Factor out the string lookup code from registry_controlled_domains

net/tools/dafsa/make_dafsa_unittest.py

 #!/usr/bin/env python
 # Copyright 2014 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 unittest
 import make_dafsa
 
@@ skipping 737 matching lines @@
     infile = [ '%%', 'aa, 1', 'bbb, 2', 'baa, 1', '%%' ]
     bytes = [ 0x02, 0x83, 0xE2, 0x02, 0x83, 0x61, 0x61, 0x81, 0x62, 0x62,
               0x82 ]
     outfile = make_dafsa.to_cxx(bytes)
     self.assertEqual(make_dafsa.words_to_cxx(make_dafsa.parse_gperf(infile)),
                       outfile)
 
 
 if __name__ == '__main__':
   unittest.main()