diff -r 000000000000 -r 6474c204b198 layout/style/nsICSSRuleList.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/style/nsICSSRuleList.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,48 @@
+/* -*- 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/. */
+
+#ifndef nsICSSRuleList_h
+#define nsICSSRuleList_h
+
+#include "nsIDOMCSSRule.h"
+#include "nsIDOMCSSRuleList.h"
+
+// IID for the nsICSSRuleList interface
+#define NS_ICSSRULELIST_IID \
+{ 0xccc0135a, 0xbcb6, 0x4654, \
+  { 0x8c, 0x78, 0x74, 0x35, 0x97, 0x9b, 0x88, 0x19 } }
+
+class nsICSSRuleList : public nsIDOMCSSRuleList
+{
+public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICSSRULELIST_IID)
+
+  NS_IMETHOD
+  GetLength(uint32_t* aLength) MOZ_OVERRIDE MOZ_FINAL
+  {
+    *aLength = Length();
+    return NS_OK;
+  }
+  NS_IMETHOD
+  Item(uint32_t aIndex, nsIDOMCSSRule** aReturn) MOZ_OVERRIDE MOZ_FINAL
+  {
+    NS_IF_ADDREF(*aReturn = Item(aIndex));
+    return NS_OK;
+  }
+
+  // WebIDL API
+  nsIDOMCSSRule* Item(uint32_t aIndex)
+  {
+    bool unused;
+    return IndexedGetter(aIndex, unused);
+  }
+
+  virtual nsIDOMCSSRule* IndexedGetter(uint32_t aIndex, bool& aFound) = 0;
+  virtual uint32_t Length() = 0;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsICSSRuleList, NS_ICSSRULELIST_IID)
+
+#endif /* nsICSSRuleList_h */