Issue #2435 - Declare PromiseRejectionEvent WebIDL

Based-on: m-c 1338059

dom/bindings/Codegen.py

@@ -80,7 +80,7 @@ def idlTypeNeedsCycleCollection(type):
         type.isObject() or
         type.isSpiderMonkeyInterface()):
         return False
-    elif type.isCallback() or type.isGeckoInterface():
+    elif type.isCallback() or type.isPromise() or type.isGeckoInterface():
         return True
     elif type.isUnion():
         return any(idlTypeNeedsCycleCollection(t) for t in type.flatMemberTypes)

dom/webidl/PromiseRejectionEvent.webidl

@@ -0,0 +1,22 @@
+/* -*- Mode: IDL; 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/.
+ *
+ * The origin of this IDL file is
+ * https://html.spec.whatwg.org/multipage/webappapis.html#the-promiserejectionevent-interface
+ */
+
+[Constructor(DOMString type, PromiseRejectionEventInit eventInitDict),
+ Exposed=(Window,Worker)]
+interface PromiseRejectionEvent : Event
+{
+  [BinaryName="rejectedPromise"]
+  readonly attribute Promise<any> promise;
+  readonly attribute any reason;
+};
+
+dictionary PromiseRejectionEventInit : EventInit {
+  required Promise<any> promise;
+           any reason;
+};

dom/webidl/moz.build

@@ -695,6 +695,7 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'PopStateEvent.webidl',
     'PopupBlockedEvent.webidl',
     'ProgressEvent.webidl',
+    'PromiseRejectionEvent.webidl',
     'RecordErrorEvent.webidl',
     'ScrollViewChangeEvent.webidl',
     'ServiceWorkerMessageEvent.webidl',