Support default values for POD struct fields in mojom IDL.

mojo/public/bindings/parse/mojo_translate.py

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 """Translate parse tree to Mojom IR"""
 
 
 import os
 import sys
@@ skipping 36 matching lines @@
       out = attribute[2]
   return out
 
 
 def MapFields(fields):
   out = []
   for field in fields:
     if field[0] == 'FIELD':
       out.append({'name': field[2],
                   'kind': MapKind(field[1]),
-                  'ordinal': MapOrdinal(field[3])})
+                  'ordinal': MapOrdinal(field[3]),
+                  'default': field[4]})
   return out
 
 
 def MapParameters(parameters):
   out = []
   for parameter in parameters:
     if parameter[0] == 'PARAM':
       out.append({'name': parameter[2],
                   'kind': MapKind(parameter[1]),
                   'ordinal': MapOrdinal(parameter[3])})
@@ skipping 87 matching lines @@
     print("usage: %s filename" % (sys.argv[0]))
     sys.exit(1)
   tree = eval(open(sys.argv[1]).read())
   name = os.path.splitext(os.path.basename(sys.argv[1]))[0]
   result = Translate(tree, name)
   print(result)
 
 
 if __name__ == '__main__':
   Main()