Stop generating MutationCallback right way.

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 re
 from htmlrenamer import html_interface_renames
 
 _pure_interfaces = set([
     # TODO(sra): DOMStringMap should be a class implementing Map<String,String>.
     'DOMStringMap',
     'ElementTimeControl',
     'ElementTraversal',
     'EventListener',
     'MediaQueryListListener',
+    'MutationCallback',
     'NodeSelector',
     'SVGExternalResourcesRequired',
     'SVGFilterPrimitiveStandardAttributes',
     'SVGFitToViewBox',
     'SVGLangSpace',
     'SVGLocatable',
     'SVGStylable',
     'SVGTests',
     'SVGTransformable',
     'SVGURIReference',
@@ skipping 1289 matching lines @@
                                   self)
 
     if type_data.clazz == 'SVGTearOff':
       dart_interface_name = self._renamer.RenameInterface(
           self._database.GetInterface(type_name))
       return SVGTearOffIDLTypeInfo(
           type_name, type_data, dart_interface_name, self)
 
     class_name = '%sIDLTypeInfo' % type_data.clazz
     return globals()[class_name](type_name, type_data)