diff -r 000000000000 -r 6474c204b198 storage/public/mozIStoragePendingStatement.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/storage/public/mozIStoragePendingStatement.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 sts=2 expandtab 
+ * 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"
+
+[scriptable, uuid(00da7d20-3768-4398-bedc-e310c324b3f0)]
+interface mozIStoragePendingStatement : nsISupports {
+
+  /**
+   * Cancels a pending statement, if possible.  This will only fail if you try
+   * cancel more than once.
+   *
+   * @note For read statements (such as SELECT), you will no longer receive any
+   *       notifications about results once cancel is called.
+   */
+   void cancel();
+};