[Merge M-56] Add canMakeActivePayment() method to web payments.

chrome/test/data/android/payments/active_payment_query.js

+/*
+ * 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.
+ */
+
+/* global PaymentRequest:false */
+/* global print:false */
+
+/**
+ * Checks for existence of Bob Pay or a complete credit card.
+ */
+function buy() {  // eslint-disable-line no-unused-vars
+  try {
+    var request = new PaymentRequest(
+        [{supportedMethods: ['https://bobpay.com', 'visa']}],
+        {total: {label: 'Total', amount: {currency: 'USD', value: '5.00'}}});
+    request.canMakeActivePayment()
+        .then(function(result) {
+          print(result);
+        })
+        .catch(function(error) {
+          print(error);
+        });
+  } catch (error) {
+    print(error.message);
+  }
+}