diff -r 000000000000 -r 6474c204b198 xpcom/glue/nsWeakReference.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/glue/nsWeakReference.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,64 @@
+/* -*- 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 nsWeakReference_h__
+#define nsWeakReference_h__
+
+// nsWeakReference.h
+
+// See mfbt/WeakPtr.h for a more typesafe C++ implementation of weak references
+
+#include "nsIWeakReferenceUtils.h"
+
+class nsWeakReference;
+
+// Set IMETHOD_VISIBILITY to empty so that the class-level NS_COM declaration
+// controls member method visibility.
+#undef  IMETHOD_VISIBILITY
+#define IMETHOD_VISIBILITY NS_COM_GLUE
+
+class NS_COM_GLUE nsSupportsWeakReference : public nsISupportsWeakReference
+  {
+    public:
+      nsSupportsWeakReference()
+          : mProxy(0)
+        {
+          // nothing else to do here
+        }
+
+      NS_DECL_NSISUPPORTSWEAKREFERENCE
+
+    protected:
+      inline ~nsSupportsWeakReference();
+
+    private:
+      friend class nsWeakReference;
+
+      void
+      NoticeProxyDestruction()
+          // ...called (only) by an |nsWeakReference| from _its_ dtor.
+        {
+          mProxy = 0;
+        }
+
+      nsWeakReference* mProxy;
+
+		protected:
+
+			void ClearWeakReferences();
+			bool HasWeakReferences() const {return mProxy != 0;}
+  };
+
+#undef  IMETHOD_VISIBILITY
+#define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN
+
+inline
+nsSupportsWeakReference::~nsSupportsWeakReference()
+  {
+  	ClearWeakReferences();
+  }
+
+#endif