diff -r 000000000000 -r 6474c204b198 xpcom/ds/nsArray.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/ds/nsArray.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 nsArray_h__
+#define nsArray_h__
+
+#include "nsIMutableArray.h"
+#include "nsCOMArray.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "mozilla/Attributes.h"
+
+// {35C66FD1-95E9-4e0a-80C5-C3BD2B375481}
+#define NS_ARRAY_CID \
+{ 0x35c66fd1, 0x95e9, 0x4e0a, \
+  { 0x80, 0xc5, 0xc3, 0xbd, 0x2b, 0x37, 0x54, 0x81 } }
+
+class nsArray : public nsIMutableArray
+{
+public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIARRAY
+    NS_DECL_NSIMUTABLEARRAY
+
+    /* Both of these factory functions create a cycle-collectable array
+       on the main thread and a non-cycle-collectable array on other
+       threads.  */
+    static already_AddRefed<nsIMutableArray> Create();
+    /* Only for the benefit of the XPCOM module system, use Create()
+       instead.  */
+    static nsresult XPCOMConstructor(nsISupports* aOuter, const nsIID& aIID,
+                                     void** aResult);
+protected:
+    nsArray() { }
+    nsArray(const nsArray& other);
+    nsArray(const nsCOMArray_base& aBaseArray) : mArray(aBaseArray)
+    { }
+    
+    virtual ~nsArray(); // nsArrayCC inherits from this
+
+    nsCOMArray_base mArray;
+};
+
+class nsArrayCC MOZ_FINAL : public nsArray
+{
+    friend class nsArray;
+
+public:
+    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTION_CLASS(nsArrayCC)
+
+private:
+    nsArrayCC() : nsArray() { }
+    nsArrayCC(const nsArrayCC& other);
+    nsArrayCC(const nsCOMArray_base& aBaseArray) : nsArray(aBaseArray)
+    { }
+};
+
+#endif