diff -r 000000000000 -r 6474c204b198 dom/base/nsDOMWindowList.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/base/nsDOMWindowList.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+/* -*- 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 nsDOMWindowList_h___
+#define nsDOMWindowList_h___
+
+#include "nsCOMPtr.h"
+#include "nsIDOMWindowCollection.h"
+#include <stdint.h>
+#include "nsIDocShell.h"
+
+class nsIDocShell;
+class nsIDOMWindow;
+
+class nsDOMWindowList : public nsIDOMWindowCollection
+{
+public:
+  nsDOMWindowList(nsIDocShell *aDocShell);
+  virtual ~nsDOMWindowList();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDOMWINDOWCOLLECTION
+
+  uint32_t GetLength();
+  already_AddRefed<nsIDOMWindow> IndexedGetter(uint32_t aIndex, bool& aFound);
+
+  //local methods
+  NS_IMETHOD SetDocShell(nsIDocShell* aDocShell);
+  already_AddRefed<nsIDocShellTreeItem> GetDocShellTreeItemAt(uint32_t aIndex)
+  {
+    EnsureFresh();
+    nsCOMPtr<nsIDocShellTreeItem> item;
+    if (mDocShellNode) {
+      mDocShellNode->GetChildAt(aIndex, getter_AddRefs(item));
+    }
+    return item.forget();
+  }
+
+protected:
+  // Note: this function may flush and cause mDocShellNode to become null.
+  void EnsureFresh();
+
+  nsIDocShell* mDocShellNode; //Weak Reference
+};
+
+#endif // nsDOMWindowList_h___