Update interfaces/push-api.idl (#17826)

Source: https://github.com/tidoust/reffy-reports/blob/52f31b9/whatwg/idl/push-api.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/563479802
diff --git a/interfaces/push-api.idl b/interfaces/push-api.idl
index 2fd5e27..74725a3 100644
--- a/interfaces/push-api.idl
+++ b/interfaces/push-api.idl
@@ -12,9 +12,9 @@
 interface PushManager {
   [SameObject] static readonly attribute FrozenArray<DOMString> supportedContentEncodings;
 
-  Promise<PushSubscription> subscribe(optional PushSubscriptionOptionsInit options);
+  Promise<PushSubscription> subscribe(optional PushSubscriptionOptionsInit options = {});
   Promise<PushSubscription?> getSubscription();
-  Promise<PushPermissionState> permissionState(optional PushSubscriptionOptionsInit options);
+  Promise<PushPermissionState> permissionState(optional PushSubscriptionOptionsInit options = {});
 };
 
 [Exposed=(Window,Worker), SecureContext]
@@ -64,7 +64,7 @@
   attribute EventHandler onpushsubscriptionchange;
 };
 
-[Constructor(DOMString type, optional PushEventInit eventInitDict), Exposed=ServiceWorker, SecureContext]
+[Constructor(DOMString type, optional PushEventInit eventInitDict = {}), Exposed=ServiceWorker, SecureContext]
 interface PushEvent : ExtendableEvent {
   readonly attribute PushMessageData? data;
 };
@@ -75,13 +75,13 @@
   PushMessageDataInit data;
 };
 
-[Constructor(DOMString type, optional PushSubscriptionChangeInit eventInitDict), Exposed=ServiceWorker, SecureContext]
+[Constructor(DOMString type, optional PushSubscriptionChangeEventInit eventInitDict = {}), Exposed=ServiceWorker, SecureContext]
 interface PushSubscriptionChangeEvent : ExtendableEvent {
   readonly attribute PushSubscription? newSubscription;
   readonly attribute PushSubscription? oldSubscription;
 };
 
-dictionary PushSubscriptionChangeInit : ExtendableEventInit {
+dictionary PushSubscriptionChangeEventInit : ExtendableEventInit {
   PushSubscription newSubscription = null;
   PushSubscription oldSubscription = null;
 };