[Payments] Implement payment instrument icons

components/payments/mojom/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/mojom/payment_request.mojom";
 import "mojo/common/time.mojom";
 import "url/mojo/url.mojom";
 
 enum PaymentHandlerStatus {
   SUCCESS,
   NOT_IMPLEMENTED,
   NOT_FOUND,
   NO_ACTIVE_WORKER,
   STORAGE_OPERATION_FAILED,
+  FETCH_INSTRUMENT_ICON_FAILED,
 };
 
+// This struct is provided to hold an image object from render side
+// (ImageObject.idl).
+struct ImageObject {
+  url.mojom.Url src;
+};
+
+// This struct is provided to hold a payment instrument from render
+// side (PaymentInstrument.idl).
 struct PaymentInstrument {
   string name;
+  array<ImageObject> icons;
   array<string> enabled_methods;
   string stringified_capabilities;
 };
 
+// This interface provides implementation of PaymentInstruments.idl
+// in render side.
 interface PaymentManager {
   Init(string service_worker_scope);
   DeletePaymentInstrument(string instrument_key)
       => (PaymentHandlerStatus status);
   GetPaymentInstrument(string instrument_key)
       => (PaymentInstrument instrument, PaymentHandlerStatus status);
   KeysOfPaymentInstruments()
       => (array<string> keys, PaymentHandlerStatus status);
   HasPaymentInstrument(string instrument_key)
       => (PaymentHandlerStatus status);
   SetPaymentInstrument(string instrument_key, PaymentInstrument instrument)
       => (PaymentHandlerStatus status);
   ClearPaymentInstruments()
       => (PaymentHandlerStatus status);
 };
 
+// This struct is provided to send payment request data to render side
+// (PaymentRequestEvent.idl).
 struct PaymentRequestEventData {
   url.mojom.Url top_level_origin;
   url.mojom.Url payment_request_origin;
   string payment_request_id;
   array<PaymentMethodData> method_data;
   PaymentItem total;
   array<PaymentDetailsModifier> modifiers;
   string instrument_key;
 };
 
+// This struct is provided to receive payment app response from render
+// side (PaymentAppResponse.idl).
 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);
 };