PaymentRequest: Add [NewObject] annotations to methods

Methods, like .complete(), show(), etc. always return a new object. They
should probably be marked as [NewObject].

This is no behavior change. So, no requires a "intent to implement".

Releated spec change:
  https://github.com/w3c/payment-request/pull/746

Bug: none
Change-Id: Ib4646a77ab7426310c42011d69c410ef104a91a4
Reviewed-on: https://chromium-review.googlesource.com/1128825Reviewed-by: Ganggui Tang <gogerald@chromium.org>
Commit-Queue: Jinho Bang <jinho.bang@samsung.com>
Cr-Commit-Position: refs/heads/master@{#573546}

third_party/blink/renderer/modules/payments/payment_request.idl

@@ -14,9 +14,9 @@
     Exposed=Window,
     ActiveScriptWrappable
 ] interface PaymentRequest : EventTarget {
-    [CallWith=ScriptState] Promise<PaymentResponse> show();
-    [CallWith=ScriptState] Promise<void> abort();
-    [CallWith=ScriptState] Promise<boolean> canMakePayment();
+    [CallWith=ScriptState, NewObject] Promise<PaymentResponse> show();
+    [CallWith=ScriptState, NewObject] Promise<void> abort();
+    [CallWith=ScriptState, NewObject] Promise<boolean> canMakePayment();
 
     readonly attribute DOMString id;
     [ImplementedAs=getShippingAddress] readonly attribute PaymentAddress? shippingAddress;

third_party/blink/renderer/modules/payments/payment_response.idl

@@ -28,5 +28,5 @@ enum PaymentComplete {
     readonly attribute DOMString? payerEmail;
     readonly attribute DOMString? payerPhone;
 
-    [CallWith=ScriptState] Promise<void> complete(optional PaymentComplete paymentResult = "unknown");
+    [CallWith=ScriptState, NewObject] Promise<void> complete(optional PaymentComplete paymentResult = "unknown");
 };