Add whitelist support for grit repack steps.

chrome/chrome_repack_locales.gypi

 # Copyright (c) 2012 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.
 
 # To use this the following variables need to be defined:
 #   pak_locales: string: the list of all the locales that need repacking
 {
   'variables': {
     'repack_locales_path': 'tools/build/repack_locales.py',
+    'repack_options%': [],
     'conditions': [
       ['branding=="Chrome"', {
         'branding_flag': ['-b', 'google_chrome',],
       }, {  # else: branding!="Chrome"
         'branding_flag': ['-b', 'chromium',],
       }],
     ],
   },
   'inputs': [
     '<(repack_locales_path)',
     '<!@pymod_do_main(repack_locales -i -p <(OS) <(branding_flag) -g <(grit_out_dir) -s <(SHARED_INTERMEDIATE_DIR) -x <(SHARED_INTERMEDIATE_DIR) --use-ash <(use_ash) <(pak_locales))'
   ],
   'outputs': [
     '<!@pymod_do_main(repack_locales -o -p <(OS) -g <(grit_out_dir) -s <(SHARED_INTERMEDIATE_DIR) -x <(SHARED_INTERMEDIATE_DIR) <(pak_locales))'
   ],
   'action': [
     'python',
     '<(repack_locales_path)',
     '<@(branding_flag)',
     '-p', '<(OS)',
     '-g', '<(grit_out_dir)',
     '-s', '<(SHARED_INTERMEDIATE_DIR)',
     '-x', '<(SHARED_INTERMEDIATE_DIR)/.',
     '--use-ash', '<(use_ash)',
+    '<@(repack_options)',
     '<@(pak_locales)',
   ],
 }