Added to options page to let users change keyboard mappings.

chrome/browser/resources/chromeos/switch_access/auto_scan_manager_unittest.gtestjs

 // 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.
 
 /**
  * @constructor
  * @implements {SwitchAccessInterface}
  */
 function FakeSwitchAccess() {
   this.moveToNextCount = 0;
-  this.switchAccessPrefs = {};
-  this.switchAccessPrefs.getNumberPref = function(key) {
+  this.getNumberPref = function(key) {
     if (key === 'autoScanTime')
       return 1;
   };
-  this.switchAccessPrefs.getBooleanPref = function(key) {
+  this.getBooleanPref = function(key) {
     if (key === 'enableAutoScan')
       return false;
   };
 };
 
 FakeSwitchAccess.prototype = {
   /** @override */
   moveToNode: function(doNext) {
     if (doNext)
       this.moveToNextCount += 1;
@@ skipping 140 matching lines @@
   assertTrue(autoScanManager.isRunning());
   assertEquals(2, autoScanManager.scanTime_);
   assertEquals(2, window.intervalDelay);
 
   autoScanManager.setScanTime(5);
   assertTrue(autoScanManager.isRunning());
   assertEquals(5, autoScanManager.scanTime_);
   assertEquals(5, window.intervalDelay);
   testDone();
 });