Use gn_helpers to [se]serialize GN lists.

build/android/gyp/finalize_splits.py

 #!/usr/bin/env python
 #
 # Copyright 2015 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.
 """Signs and zipaligns split APKs.
 
 This script is require only by GYP (not GN).
 """
 
@@ skipping 23 matching lines @@
 
   if options.densities:
     for density in options.densities.split(','):
       options.unsigned_apk_path = ("%s_%s" %
           (options.resource_packaged_apk_path, density))
       options.final_apk_path = ("%s-density-%s.apk" %
           (options.base_output_path, density))
       finalize_apk.FinalizeApk(options)
 
   if options.languages:
-    for lang in build_utils.ParseGypList(options.languages):
+    for lang in build_utils.ParseGnList(options.languages):
       options.unsigned_apk_path = ("%s_%s" %
           (options.resource_packaged_apk_path, lang))
       options.final_apk_path = ("%s-lang-%s.apk" %
           (options.base_output_path, lang))
       finalize_apk.FinalizeApk(options)
 
 if __name__ == '__main__':
   sys.exit(main())