diff -r 000000000000 -r 6474c204b198 dom/promise/PromiseNativeHandler.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/promise/PromiseNativeHandler.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,39 @@
+/* -*- Mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; tab-width: 40 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* 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 mozilla_dom_PromiseNativeHandler_h
+#define mozilla_dom_PromiseNativeHandler_h
+
+#include "nsISupports.h"
+
+namespace mozilla {
+namespace dom {
+
+/*
+ * PromiseNativeHandler allows C++ to react to a Promise being rejected/resolved.
+ * A PromiseNativeHandler can be appended to a Promise using
+ * Promise::AppendNativeHandler().
+ */
+class PromiseNativeHandler : public nsISupports
+{
+public:
+  // NS_IMPL_ISUPPORTS0 in Promise.cpp.
+  NS_DECL_ISUPPORTS
+
+  virtual ~PromiseNativeHandler()
+  { }
+
+  virtual void
+  ResolvedCallback(JS::Handle<JS::Value> aValue) = 0;
+
+  virtual void
+  RejectedCallback(JS::Handle<JS::Value> aValue) = 0;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_PromiseNativeHandler_h