PaymentHandler: Implement PaymentRequestEvent constructor.

third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl

Index: third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
diff --git a/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl b/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
index 2083df69599e407ef737f1169684fd9ea031b7b9..b91490965c02844dccc96baa7731af0eac5979ae 100644
--- a/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
+++ b/third_party/WebKit/Source/modules/payments/PaymentRequestEvent.idl
@@ -4,14 +4,13 @@
 
 // https://w3c.github.io/payment-handler/#the-paymentrequestevent
 
-// TODO(zino): Once the spec issue is resolved, we should apply the changes.
-// Please see https://github.com/w3c/payment-handler/pull/162
 [
     RuntimeEnabled=PaymentApp,
+    Constructor(DOMString type, PaymentRequestEventInit eventInitDict),
     Exposed=ServiceWorker
 ] interface PaymentRequestEvent : ExtendableEvent {
-    readonly attribute DOMString topLevelOrigin;
-    readonly attribute DOMString paymentRequestOrigin;
+    readonly attribute USVString topLevelOrigin;
+    readonly attribute USVString paymentRequestOrigin;
     readonly attribute DOMString paymentRequestId;
     readonly attribute sequence<PaymentMethodData> methodData;
     readonly attribute PaymentItem total;