Clean-up blink_idl_parser

tools/idl_parser/idl_parser.py

 #!/usr/bin/env python
 # Copyright (c) 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.
 
 """ Parser for PPAPI IDL """
 
 #
 # IDL Parser
 #
@@ skipping 196 matching lines @@
   # [2.1] Error recovery for definition
   def p_DefinitionError(self, p):
     """Definition : error ';'"""
     p[0] = self.BuildError(p, 'Definition')
 
   # [3]
   def p_CallbackOrInterface(self, p):
     """CallbackOrInterface : CALLBACK CallbackRestOrInterface
                            | Interface"""
     if len(p) > 2:
+      p[2].AddChildren(self.BuildTrue('CALLBACK'))
       p[0] = p[2]
     else:
       p[0] = p[1]
 
   # [4]
   def p_CallbackRestOrInterface(self, p):
     """CallbackRestOrInterface : CallbackRest
                                | Interface"""
     p[0] = p[1]
 
@@ skipping 1071 matching lines @@
 
   print '\n'.join(ast.Tree(accept_props=['PROD']))
   if errors:
     print '\nFound %d errors.\n' % errors
 
   return errors
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))