[Payments] Implement openWindow for service worker based payment handler

content/test/data/payments/payment_app.js

 // Copyright 2017 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.
 
 self.addEventListener('paymentrequest', e => {
   e.waitUntil(clients.matchAll({includeUncontrolled: true}).then(clients => {
     clients.forEach(client => {
       if (client.url.indexOf('payment_app_invocation.html') != -1) {
         client.postMessage(e.topLevelOrigin);
         client.postMessage(e.paymentRequestOrigin);
         client.postMessage(e.paymentRequestId);
         client.postMessage(JSON.stringify(e.methodData));
         client.postMessage(JSON.stringify(e.total));
         client.postMessage(JSON.stringify(e.modifiers));
         client.postMessage(e.instrumentKey);
       }
     });
   }));
 
   // SW -------------------- openWindow() ------------------> payment_app_window
   // SW <----- postMessage('payment_app_window_ready') ------ payment_app_window
   // SW -------- postMessage('payment_app_request') --------> payment_app_window
   // SW <-- postMessage({methodName: 'test', details: {}}) -- payment_app_window
-  e.respondWith(new Promise(resolve => {
+  e.respondWith(new Promise((resolve, reject) => {
     let payment_app_window = undefined;
     let window_ready = false;
 
     let maybeSendPaymentRequest = function() {
       if (payment_app_window && window_ready)
         payment_app_window.postMessage('payment_app_request');
     };
 
     self.addEventListener('message', e => {
       if (e.data == "payment_app_window_ready") {
         window_ready = true;
         maybeSendPaymentRequest();
         return;
       }
 
       if (e.data.methodName) {
         resolve(e.data);
         return;
       }
     });
 
-    // Open a window
-    clients.openWindow('payment_app_window.html')
+    // Open a window for the payment instrument.
+    var payment_app_web_page = 'payment_app_window.html';
+    if(e.instrumentKey == 'bobpay-payment-app-id') {
+      payment_app_web_page = 'https://bobpay.com';
+    }
+    e.openWindow(payment_app_web_page)
       .then(window_client => {
         payment_app_window = window_client;
         maybeSendPaymentRequest();
       })
+      .catch(error => {
+        reject(error);
+      });
   }));
 });