diff -r 000000000000 -r 6474c204b198 addon-sdk/source/lib/sdk/core/reference.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/addon-sdk/source/lib/sdk/core/reference.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+/* 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/. */
+
+"use strict";
+
+module.metadata = {
+  "stability": "experimental"
+};
+
+const method = require("../../method/core");
+const { Class } = require("./heritage");
+
+// Object that inherit or mix WeakRefence inn will register
+// weak observes for system notifications.
+const WeakReference = Class({});
+exports.WeakReference = WeakReference;
+
+
+// If `isWeak(object)` is `true` observer installed
+// for such `object` will be weak, meaning that it will
+// be GC-ed if nothing else but observer is observing it.
+// By default everything except `WeakReference` will return
+// `false`.
+const isWeak = method("reference/weak?");
+exports.isWeak = isWeak;
+
+isWeak.define(Object, _ => false);
+isWeak.define(WeakReference, _ => true);