diff -r 000000000000 -r 6474c204b198 xpcom/ds/nsIObserverService.idl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/ds/nsIObserverService.idl	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,77 @@
+/* -*- 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/. */
+
+#include "nsISupports.idl"
+
+interface nsIObserver;
+interface nsISimpleEnumerator;
+
+/**
+ * nsIObserverService
+ * 
+ * Service allows a client listener (nsIObserver) to register and unregister for 
+ * notifications of specific string referenced topic. Service also provides a 
+ * way to notify registered listeners and a way to enumerate registered client 
+ * listeners.
+ */
+
+[scriptable, uuid(D07F5192-E3D1-11d2-8ACD-00105A1B8860)]
+interface nsIObserverService : nsISupports 
+{
+
+    /**
+     * AddObserver
+     *
+     * Registers a given listener for a notifications regarding the specified
+     * topic.
+     *
+     * @param anObserve : The interface pointer which will receive notifications.
+     * @param aTopic    : The notification topic or subject.
+     * @param ownsWeak  : If set to false, the nsIObserverService will hold a 
+     *                    strong reference to |anObserver|.  If set to true and 
+     *                    |anObserver| supports the nsIWeakReference interface,
+     *                    a weak reference will be held.  Otherwise an error will be
+     *                    returned.
+     */
+ 	void addObserver( in nsIObserver anObserver, in string aTopic, in boolean ownsWeak);
+
+    /**
+     * removeObserver
+     *
+     * Unregisters a given listener from notifications regarding the specified
+     * topic.
+     *
+     * @param anObserver : The interface pointer which will stop recieving
+     *                     notifications.
+     * @param aTopic     : The notification topic or subject.
+     */
+    void removeObserver( in nsIObserver anObserver, in string aTopic );
+
+    /**
+     * notifyObservers
+     *
+     * Notifies all registered listeners of the given topic.
+     *
+     * @param aSubject : Notification specific interface pointer.
+     * @param aTopic   : The notification topic or subject.
+     * @param someData : Notification specific wide string.
+     */
+    void notifyObservers( in nsISupports aSubject, 
+                          in string aTopic, 
+                          in wstring someData );
+
+    /**
+     * enumerateObservers
+     *
+     * Returns an enumeration of all registered listeners.
+     *
+     * @param aTopic   : The notification topic or subject.
+     */
+	nsISimpleEnumerator enumerateObservers( in string aTopic );
+
+
+};
+
+