Add .eslintrc.js to chrome/test/data/webui/signin

Fix implicit global, use of 'var', and binding a variable 'arguments'.

Bug: none
Test: browser_tests
Change-Id: Ibfecdac67163f2b09e0c10ea9fc17696e1eaf1dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1641519
Commit-Queue: James Cook <jamescook@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#665972}

chrome/test/data/webui/signin/.eslintrc.js

+// Copyright 2019 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.exports = {
+  'rules': {
+    'no-var': 'error',
+  },
+};

chrome/test/data/webui/signin/signin_browsertest.js

@@ -14,7 +14,8 @@ GEN('#include "chrome/test/data/webui/signin_browsertest.h"');
  * chrome/browser/resources/signin/dice_sync_confirmation/sync_confirmation.html.
  * This has to be declared as a variable for TEST_F to find it correctly.
  */
-SigninSyncConfirmationTest = class extends PolymerTest {
+// eslint-disable-next-line no-var
+var SigninSyncConfirmationTest = class extends PolymerTest {
   /** @override */
   get typedefCppFixture() {
     return 'SigninBrowserTest';

chrome/test/data/webui/signin/sync_confirmation_test.js

@@ -9,7 +9,7 @@ cr.define('signin_sync_confirmation', function() {
     setup(function() {
       PolymerTest.clearBody();
       app = document.createElement('sync-confirmation-app');
-      var accountImageRequested = false;
+      let accountImageRequested = false;
       registerMessageCallback('accountImageRequest', this, function() {
         accountImageRequested = true;
       });
@@ -62,11 +62,8 @@ cr.define('signin_sync_confirmation', function() {
     // button.
     test('recordConsentOnConfirm', function() {
       app.$$('#confirmButton').click();
-      return browserProxy.whenCalled('confirm').then(function(arguments) {
-        assertEquals(2, arguments.length);
-        var description = arguments[0];
-        var confirmation = arguments[1];
-
+      return browserProxy.whenCalled('confirm').then(function(
+          [description, confirmation]) {
         assertEquals(
             JSON.stringify(STANDARD_CONSENT_DESCRIPTION_TEXT),
             JSON.stringify(description));
@@ -78,11 +75,9 @@ cr.define('signin_sync_confirmation', function() {
     // button.
     test('recordConsentOnSettingsLink', function() {
       app.$$('#settingsButton').click();
-      return browserProxy.whenCalled('goToSettings').then(function(arguments) {
-        assertEquals(2, arguments.length);
-        var description = arguments[0];
-        var confirmation = arguments[1];
-
+      return browserProxy.whenCalled('goToSettings').then(function([
+        description, confirmation
+      ]) {
         assertEquals(
             JSON.stringify(STANDARD_CONSENT_DESCRIPTION_TEXT),
             JSON.stringify(description));