Fix the build script to be able to build more than one generator.

mojom/tools/build_generators.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
 """Builds and optionally uploads the mojom generators to Google Cloud Storage.
 
 This script works the same as build_mojom_tool.
 """
 
 import os
 import sys
 
 import builder
 
 
 def main():
-  parser = builder.get_arg_parser("Build the mojom generators.")
+  parser = builder.get_arg_parser('Build the mojom generators.')
+  parser.add_argument('--generators', dest='generators', type=str, default=None,
+      action='store', help='')

[rudominer, 2016/04/25 23:16:05]

I think a help string with an example would be useful.

[azani, 2016/04/26 00:03:27]

Woops, I forgot the help string. Right now, there is only deps, so I don't think
an example is useful here.

   args = parser.parse_args()
 
   generators = [
       'deps',

[rudominer, 2016/04/25 23:16:05]

The default should be to build all of the generators, right?

[azani, 2016/04/26 00:03:27]

It is.

       ]
 
+  if args.generators:
+    generators = args.generators.split(',')
+
   final_result = 0
   for generator in generators:
     generator_builder = builder.get_builder(
         args=args,
         target_dir='generators',
         binary_name=generator,
         src_path=os.path.join('mojom', 'generators', generator))
 
     if args.upload:
       result = generator_builder.build_and_upload()
     result = generator_builder.build()
     if result != 0:
       final_result = result
       if not args.keep_going:
         return result
 
-    return final_result
+  return final_result
 
 
 if __name__ == '__main__':
   sys.exit(main())