Support 'Conditional' idl attribute.

client/dom/generated/src/interface/HTMLPropertiesCollection.dart

Index: client/dom/generated/src/interface/HTMLPropertiesCollection.dart
diff --git a/client/dom/generated/src/interface/HTMLPropertiesCollection.dart b/client/dom/generated/src/interface/HTMLPropertiesCollection.dart
deleted file mode 100644
index 913690cf1f743f5cb0d15bcbf9b5c137794fcfe0..0000000000000000000000000000000000000000
--- a/client/dom/generated/src/interface/HTMLPropertiesCollection.dart
+++ /dev/null
@@ -1,12 +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.
-
-interface HTMLPropertiesCollection extends HTMLCollection {
-
-  int get length();
-
-  Node item(int index);
-}