Add property to CssStyleDeclaration to detect if a CSS value is available.

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 1142 matching lines @@
     'Dictionary': TypeData(clazz='Primitive', dart_type='Map'),
     'DOMTimeStamp': TypeData(clazz='Primitive', dart_type='int', native_type='unsigned long long'),
     'object': TypeData(clazz='Primitive', dart_type='Object', native_type='ScriptValue'),
     'ObjectArray': TypeData(clazz='Primitive', dart_type='List'),
     'PositionOptions': TypeData(clazz='Primitive', dart_type='Object'),
     # TODO(sra): Come up with some meaningful name so that where this appears in
     # the documentation, the user is made aware that only a limited subset of
     # serializable types are actually permitted.
     'SerializedScriptValue': TypeData(clazz='Primitive', dart_type='dynamic'),
     'sequence': TypeData(clazz='Primitive', dart_type='List'),
+    'union': TypeData(clazz='Primitive', dart_type='dynamic'),
     'void': TypeData(clazz='Primitive', dart_type='void'),
 
     'CSSRule': TypeData(clazz='Interface', conversion_includes=['CSSImportRule']),
     'DOMStringMap': TypeData(clazz='Interface', dart_type='Map<String, String>'),
     'Window': TypeData(clazz='Interface', custom_to_dart=True),
     'Element': TypeData(clazz='Interface', merged_interface='HTMLElement',
         custom_to_dart=True),
     'EventListener': TypeData(clazz='Interface', custom_to_native=True),
     'EventHandler': TypeData(clazz='Interface', custom_to_native=True),
     'EventTarget': TypeData(clazz='Interface', custom_to_native=True),
@@ skipping 144 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)