diff -r 000000000000 -r 6474c204b198 xpcom/ds/nsObserverService.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/ds/nsObserverService.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+/* -*- 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 nsObserverService_h___
+#define nsObserverService_h___
+
+#include "nsIObserverService.h"
+#include "nsObserverList.h"
+#include "nsIMemoryReporter.h"
+#include "nsTHashtable.h"
+#include "mozilla/Attributes.h"
+
+// {D07F5195-E3D1-11d2-8ACD-00105A1B8860}
+#define NS_OBSERVERSERVICE_CID \
+    { 0xd07f5195, 0xe3d1, 0x11d2, { 0x8a, 0xcd, 0x0, 0x10, 0x5a, 0x1b, 0x88, 0x60 } }
+
+class nsIMemoryReporter;
+
+class nsObserverService MOZ_FINAL
+  : public nsIObserverService
+  , public nsIMemoryReporter
+{
+public:
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_OBSERVERSERVICE_CID)
+
+  nsObserverService();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVERSERVICE
+  NS_DECL_NSIMEMORYREPORTER
+
+  void Shutdown();
+
+  static nsresult
+  Create(nsISupports* outer, const nsIID& aIID, void* *aInstancePtr);
+
+  // Unmark any strongly held observers implemented in JS so the cycle
+  // collector will not traverse them.
+  NS_IMETHOD UnmarkGrayStrongObservers();
+
+private:
+  ~nsObserverService(void);
+  void RegisterReporter();
+
+  static const size_t kSuspectReferentCount = 100;
+  static PLDHashOperator CountReferents(nsObserverList* aObserverList,
+                                        void* aClosure);
+  bool mShuttingDown;
+  nsTHashtable<nsObserverList> mObserverTopicTable;
+};
+
+NS_DEFINE_STATIC_IID_ACCESSOR(nsObserverService, NS_OBSERVERSERVICE_CID)
+
+#endif /* nsObserverService_h___ */