Chrome roll.

tools/dom/scripts/systemhtml.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 the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 import monitored
@@ skipping 633 matching lines @@
           " && (new %sElement.tag('%s') is %s)" % (lib_prefix,
         constructors[self._interface.doc_js_name],
         self._renamer.RenameInterface(self._interface)))
     return js_support_checks.get(self._interface.doc_js_name)
 
   def GenerateCustomFactory(self, constructor_info):
     # Custom factory will be taken from the template.
     return self._interface.doc_js_name in _js_custom_constructors
 
   def IsConstructorArgumentOptional(self, argument):
-    return 'Optional' in argument.ext_attrs
+    return argument.optional
 
   def EmitStaticFactoryOverload(self, constructor_info, name, arguments):
     index = len(arguments)
     arguments = constructor_info.ParametersAsArgumentList(index)
     if arguments:
       arguments = ', ' + arguments
     self._members_emitter.Emit(
         "  static $INTERFACE_NAME $NAME($PARAMETERS) => "
           "JS('$INTERFACE_NAME', 'new $CTOR_NAME($PLACEHOLDERS)'$ARGUMENTS);\n",
         INTERFACE_NAME=self._interface_type_info.interface_name(),
@@ skipping 322 matching lines @@
         self._Annotations(info.type_name, info.declared_name),
         'static ' if info.IsStatic() else '',
         return_type,
         html_name,
         info.ParametersDeclaration(InputType))
     self._GenerateDispatcherBody(
         operations,
         parameter_names,
         declaration,
         GenerateCall,
-        self._IsOptional,
+        lambda _, argument: IsOptional(argument),
         can_omit_type_check=lambda type, pos: type == parameter_types[pos])
 
   def _AddInterfaceOperation(self, info, html_name):
     self._members_emitter.Emit(
         '\n'
         '  $TYPE $NAME($PARAMS);\n',
         TYPE=self.SecureOutputType(info.type_name),
         NAME=info.name,
         PARAMS=info.ParametersDeclaration(self._NarrowInputType))
 
-  def _IsOptional(self, operation, argument):
-    return IsOptional(argument)
-
 
   def _OperationRequiresConversions(self, operation):
     return (self._OperationRequiresOutputConversion(operation) or
             self._OperationRequiresInputConversions(operation))
 
   def _OperationRequiresOutputConversion(self, operation):
     return self._OutputConversion(operation.type.id, operation.id)
 
   def _OperationRequiresInputConversions(self, operation):
     return any(self._InputConversion(arg.type.id, operation.id)
@@ skipping 138 matching lines @@
     for library_name in libraries:
       self._libraries[library_name] = DartLibrary(
           library_name, template_loader, library_type, output_dir)
 
   def AddFile(self, basename, library_name, path):
     self._libraries[library_name].AddFile(path)
 
   def Emit(self, emitter, auxiliary_dir):
     for lib in self._libraries.values():
       lib.Emit(emitter, auxiliary_dir)