diff -r 000000000000 -r 6474c204b198 dom/interfaces/css/nsIDOMCSSGroupingRule.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/interfaces/css/nsIDOMCSSGroupingRule.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,21 @@
+/* -*- Mode: IDL; 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 "nsIDOMCSSRule.idl"
+
+/**
+ * Interface for at-rules that have child rules in the CSS OM.
+ */
+[scriptable, uuid(ab013eed-fa21-4c6a-bba3-79e8780f583e)]
+interface nsIDOMCSSGroupingRule : nsIDOMCSSRule
+{
+  readonly attribute nsIDOMCSSRuleList cssRules;
+
+  unsigned long      insertRule(in DOMString rule,
+                                in unsigned long index)
+                                        raises(DOMException);
+  void               deleteRule(in unsigned long index)
+                                        raises(DOMException);
+};