PaymentApp: Implement respondWith() in PaymentRequestEvent. (content side)

components/payments/content/payment_app.mojom

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module payments.mojom;
 
 import "components/payments/content/payment_request.mojom";
 import "url/mojo/url.mojom";
 
 enum PaymentAppManifestError {
@@ skipping 24 matching lines @@
       => (PaymentAppManifest payment_app_manifest, PaymentAppManifestError error);
 };
 
 struct PaymentAppRequest {
   url.mojom.Url origin;
   array<PaymentMethodData> methodData;
   PaymentItem total;
   array<PaymentDetailsModifier> modifiers;
   string optionId;
 };
+
+struct PaymentAppResponse {
+  string method_name;

[Tom Sepez, 2017/03/07 17:22:39]

What are the restrictions on the values of these two fields?
These are only processed in a renderer?

[zino, 2017/03/27 15:27:04]

As I know, there are no restrictions in spec side.
The spec says that "Payment method security is outside the scope of this
specification and is addressed by payment handlers that support those payment
methods.".

The spec concept is providing a web based payment app using JS with service
worker.
So, we can not sure that the payment app provider what they want. So, it is
difficult to restrict the values of the method and details explicitly.

I think we can add length limits for them. Do we need them in mojo?

+  string stringified_details;
+};