Add a switch in BUILD rules to control the generation of type info for mojom files.

mojo/public/tools/bindings/run_code_generators.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.
 #
 # This script accepts the output of version 2 of the mojom parser and uses that
 # data to invoke the code generators.
 
 import argparse
 import imp
@@ skipping 32 matching lines @@
                       help="Generate code only for the files that are "
                       "specified on the command line. By default, code "
                       "is generated for all specified files and their "
                       "transitive imports.")
   parser.add_argument("--generate-type-info", dest="generate_type_info",
                       action="store_true",
                       help="generate mojom type descriptors")
   parser.add_argument("--no-generate-type-info", dest="generate_type_info",
                       action="store_false",
                       help="do not generate mojom type descriptors")
-  parser.set_defaults(generate_type_info=True)
+  parser.set_defaults(generate_type_info=False)
 
   return parser.parse_known_args()
 
 # We assume this script is located in the Mojo SDK in tools/bindings.
 THIS_DIR = os.path.abspath(os.path.dirname(__file__))
 SDK_ROOT = os.path.abspath(os.path.join(THIS_DIR, os.pardir, os.pardir))
 PYTHON_SDK_DIR = os.path.abspath(os.path.join(SDK_ROOT, "python"))
 
 def _FixPath():
   # We parse command line args before imports in case the caller wishes to
@@ skipping 123 matching lines @@
         filtered_args = [arg for arg in remaining_args
                          if arg.startswith(prefix)]
       if args.generate_type_info:
         filtered_args.append("--generate_type_info")
 
       generator.GenerateFiles(filtered_args)
 
 
 if __name__ == "__main__":
   sys.exit(main())