diff -r 000000000000 -r 6474c204b198 layout/xul/tree/nsITreeContentView.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/tree/nsITreeContentView.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsISupports.idl"
+
+interface nsIDOMElement;
+
+[scriptable, uuid(5ef62896-0c0a-41f1-bb3c-44a60f5dfdab)]
+interface nsITreeContentView : nsISupports
+{
+  /**
+   * Retrieve the content item associated with the specified index.
+   */
+  nsIDOMElement getItemAtIndex(in long index);
+
+  /**
+   * Retrieve the index associated with the specified content item.
+   */
+  long getIndexOfItem(in nsIDOMElement item);
+};