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 "mojo/common/time.mojom";
 import "url/mojo/url.mojom";
 
 enum PaymentAppManifestError {
   NONE,
   NOT_IMPLEMENTED,
   NO_ACTIVE_WORKER,
   MANIFEST_STORAGE_OPERATION_FAILED,
 };
 
 struct PaymentAppOption {
@@ skipping 17 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;
+  string stringified_details;
+};
+
+// This interface is provided to pass a payment app response from payment
+// request event in renderer side to browser side by calling respondWith().
+interface PaymentAppResponseCallback {
+  OnPaymentAppResponse(PaymentAppResponse response,
+                       mojo.common.mojom.Time dispatch_event_time);
+};