Fix handling default parameters

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 210 matching lines @@
 # Given a list of overloaded arguments, render dart arguments.
 def _BuildArguments(args, interface, constructor=False):
   def IsOptional(argument):
     if 'Callback' in argument.ext_attrs:
       # Optional callbacks arguments are treated as optional arguments.
       return argument.optional
     if constructor:
       # FIXME: Optional constructors arguments should not be treated as
       # optional arguments.
       return argument.optional
-    if 'ForceOptional' in argument.ext_attrs:
+    if 'DartForceOptional' in argument.ext_attrs:
       return True
     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
@@ skipping 13 matching lines @@
   for arg_tuple in map(lambda *x: x, *args):
     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
 
+# Argument default value set (literal value or null).
+def HasDefault(argument):
+  return (argument.default_value != None) or argument.default_value_is_null
+
 def IsOptional(argument):
-  return argument.optional and ('Default' not in argument.ext_attrs)\
-      or 'ForceOptional' in argument.ext_attrs
+  return argument.optional and (not(HasDefault(argument))) \
+         or 'DartForceOptional' 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 1039 matching lines @@
     if type_data.clazz == 'BasicTypedList':
       if type_name == 'ArrayBuffer':
         dart_interface_name = 'ByteBuffer'
       else:
         dart_interface_name = self._renamer.RenameInterfaceId(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)