Relation list properties for Accessibility Object Model phase 1

third_party/WebKit/Source/core/dom/AccessibleNodeList.idl

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Accessibility Object Model node list
+// Explainer: https://github.com/WICG/aom/blob/master/explainer.md
+// Spec: https://wicg.github.io/aom/spec/
+[
+    Constructor(optional sequence<AccessibleNode> nodes = []),
+    RuntimeEnabled=AccessibilityObjectModel
+] interface AccessibleNodeList {
+  attribute unsigned long length;
+  getter AccessibleNode? item(unsigned long index);
+  [RaisesException] setter void (unsigned long index, AccessibleNode node);
+  void add(AccessibleNode node, optional AccessibleNode? before = null);
+  void remove(long index);
+};