Chrome roll.

tools/dom/scripts/generator.py

 #!/usr/bin/python
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 """This module provides shared functionality for systems to generate
 Dart APIs from the IDL database."""
 
 import copy
 import json
@@ skipping 125 matching lines @@
   """For the given interface, find operations that take callbacks (for use in
   auto-transforming callbacks into futures)."""
   callback_handlers = [operation for operation in interface.operations
       if operation.id == 'handleEvent']
   return AnalyzeOperation(interface, callback_handlers)
 
 # Given a list of overloaded arguments, render dart arguments.
 def _BuildArguments(args, interface, constructor=False):
   def IsOptional(argument):
     if 'Callback' in argument.ext_attrs:
-      # Callbacks with 'Optional=XXX' are treated as optional arguments.
-      return 'Optional' in argument.ext_attrs
+      # Optional callbacks arguments are treated as optional arguments.
+      return argument.optional
     if constructor:
-      # FIXME: Constructors with 'Optional=XXX' shouldn't be treated as
+      # FIXME: Optional constructors arguments should not be treated as
       # optional arguments.
-      return 'Optional' in argument.ext_attrs
+      return argument.optional
     return False
 
   # Given a list of overloaded arguments, choose a suitable name.
   def OverloadedName(args):
     return '_OR_'.join(sorted(set(arg.id for arg in args)))
 
   def DartType(idl_type_name):
    if idl_type_name in _idl_type_registry:
      return _idl_type_registry[idl_type_name].dart_type or idl_type_name
    return idl_type_name
@@ skipping 13 matching lines @@
     is_optional = is_optional or any(arg is None or IsOptional(arg) for arg in arg_tuple)
 
     filtered = filter(None, arg_tuple)
     type_id = OverloadedType(filtered)
     name = OverloadedName(filtered)
     result.append(ParamInfo(name, type_id, is_optional))
 
   return result
 
 def IsOptional(argument):
-  return ('Optional' in argument.ext_attrs and
-          argument.ext_attrs['Optional'] == None)
+  return argument.optional and ('Default' not in argument.ext_attrs)
 
 def AnalyzeOperation(interface, operations):
   """Makes operation calling convention decision for a set of overloads.
 
   Returns: An OperationInfo object.
   """
 
   # split operations with optional args into multiple operations
   split_operations = []
   for operation in operations:
@@ skipping 1390 matching lines @@
           type_name, type_data, dart_interface_name, self)
 
     if type_data.clazz == 'BasicTypedList':
       dart_interface_name = self._renamer.RenameInterface(
           self._database.GetInterface(type_name))
       return BasicTypedListIDLTypeInfo(
           type_name, type_data, dart_interface_name, self)
 
     class_name = '%sIDLTypeInfo' % type_data.clazz
     return globals()[class_name](type_name, type_data)