Update PromiseRejectionEvent IDL to match latest spec

https://github.com/whatwg/html/pull/224

R=domenic@chromium.org
BUG=495801

Review URL: https://codereview.chromium.org/1471283002

Cr-Commit-Position: refs/heads/master@{#361412}

third_party/WebKit/LayoutTests/fast/events/constructors/promise-rejection-event-constructor.html

@@ -8,17 +8,17 @@
 test(function() {
   var p = new Promise(function(resolve, reject) {});
 
-  // No initializer is passed.
-  assert_equals(new PromiseRejectionEvent('eventType').bubbles, false);
-  assert_equals(new PromiseRejectionEvent('eventType').cancelable, false);
-  assert_equals(new PromiseRejectionEvent('eventType').promise, null);
-  assert_equals(new PromiseRejectionEvent('eventType').reason, null);
+  // No custom options are passed (besides required promise).
+  assert_equals(new PromiseRejectionEvent('eventType', { promise: p }).bubbles, false);
+  assert_equals(new PromiseRejectionEvent('eventType', { promise: p }).cancelable, false);
+  assert_equals(new PromiseRejectionEvent('eventType', { promise: p }).promise, p);
+  assert_equals(new PromiseRejectionEvent('eventType', { promise: p }).reason, undefined);
 
   // No promise is passed.
   assert_throws(new TypeError(),
                 function() {
                   new PromiseRejectionEvent('eventType', { bubbles: false });
-                }, 
+                },
                 'Cannot construct PromiseRejectionEventInit without promise');
 
   // bubbles is passed.
@@ -29,9 +29,6 @@ test(function() {
   assert_equals(new PromiseRejectionEvent('eventType', { cancelable: false, promise: p }).cancelable, false);
   assert_equals(new PromiseRejectionEvent('eventType', { cancelable: true, promise: p }).cancelable, true);
 
-  // promise is passed.
-  assert_equals(new PromiseRejectionEvent('eventType', { promise: p }).promise, p);
-
   // reason is passed.
   var r = new Error();
   assert_equals(new PromiseRejectionEvent('eventType', { promise: p, reason: r }).reason, r);

third_party/WebKit/Source/core/events/PromiseRejectionEvent.cpp

@@ -44,7 +44,7 @@ ScriptValue PromiseRejectionEvent::reason(ScriptState* state) const
 {
     // Return null when the value is accessed by a different world than the world that created the value.
     if (m_reason.isEmpty() || !m_scriptState || !m_scriptState->contextIsValid() || m_scriptState->world().worldId() != state->world().worldId())
-        return ScriptValue(state, v8::Null(state->isolate()));
+        return ScriptValue(state, v8::Undefined(state->isolate()));
     return ScriptValue(m_scriptState.get(), m_reason.newLocal(m_scriptState->isolate()));
 }
 

third_party/WebKit/Source/core/events/PromiseRejectionEvent.idl

@@ -7,10 +7,10 @@
 [
     RuntimeEnabled=PromiseRejectionEvent,
     Custom=VisitDOMWrapper,
-    Constructor(DOMString type, optional PromiseRejectionEventInit eventInitDict),
+    Constructor(DOMString type, PromiseRejectionEventInit eventInitDict),
     ConstructorCallWith=ScriptState,
     Exposed=(Window,Worker,ServiceWorker),
 ] interface PromiseRejectionEvent : Event {
-    [Custom=Getter] readonly attribute Promise<any>? promise;
+    [Custom=Getter] readonly attribute Promise<any> promise;
     [CallWith=ScriptState] readonly attribute any reason;
 };

third_party/WebKit/Source/core/events/PromiseRejectionEventInit.idl

@@ -7,6 +7,6 @@
 [
     RuntimeEnabled=PromiseRejectionEvent,
 ] dictionary PromiseRejectionEventInit : EventInit {
-    required Promise<any>? promise;
-    any reason = null;
+    required Promise<any> promise;
+    any reason;
 };