Use fake Input Device Settings with chrome://device-emulator

chrome/browser/resources/chromeos/emulator/battery_settings.js

 // Copyright 2015 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.
 
 var BatterySettings = Polymer({
   is: 'battery-settings',
 
   behaviors: [Polymer.NeonAnimatableBehavior],
 
   properties: {
@@ skipping 59 matching lines @@
     timeUntilEmpty: String,
 
     /** A string representing the time left until the battery is at 100%. */
     timeUntilFull: String,
   },
 
   observers: [
     'powerSourcesChanged(powerSourceOptions.*)',
   ],
 
-  initialize: function() {
-    if (!this.initialized) {
-      chrome.send('requestPowerInfo');
-      this.initialized = true;
-    }
+  ready: function() {
+    chrome.send('requestPowerInfo');
   },
 
   onBatteryPercentChange: function(e) {
     this.percent = parseInt(e.target.value);
     if (!isNaN(this.percent))
       chrome.send('updateBatteryPercent', [this.percent]);
   },
 
   onSetAsSourceTap: function(e) {
     chrome.send('updatePowerSourceId', [e.model.item.id]);
@@ skipping 53 matching lines @@
   },
 
   canBecomeSource: function(source, selectedId, powerSourceOptionsChange) {
     if (!source.connected || !this.isDualRole(source))
       return false;
     return !this.powerSourceOptions.some(function(source) {
       return source.connected && source.type == 'DedicatedCharger';
     });
   },
 });