Support 'Conditional' idl attribute.

client/dom/generated/src/wrapping/_MutationCallbackWrappingImplementation.dart

Index: client/dom/generated/src/wrapping/_MutationCallbackWrappingImplementation.dart
diff --git a/client/dom/generated/src/wrapping/_MutationCallbackWrappingImplementation.dart b/client/dom/generated/src/wrapping/_MutationCallbackWrappingImplementation.dart
deleted file mode 100644
index f807aebf97fbff7a79691a365cfdc34335f16bcc..0000000000000000000000000000000000000000
--- a/client/dom/generated/src/wrapping/_MutationCallbackWrappingImplementation.dart
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright (c) 2011, 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.
-
-// WARNING: Do not edit - generated code.
-
-class _MutationCallbackWrappingImplementation extends DOMWrapperBase implements MutationCallback {
-  _MutationCallbackWrappingImplementation() : super() {}
-
-  static create__MutationCallbackWrappingImplementation() native {
-    return new _MutationCallbackWrappingImplementation();
-  }
-
-  String get typeName() { return "MutationCallback"; }
-}