Creating Ui for Battery State Option in Chrome Os 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',
 
   properties: {
     /**
      * The system's battery percentage.
      */
     batteryPercent: {
       type: Number,
+      observer: 'batteryPercentChanged',
     },
 
     /**
-     * A string representing the value of an
+     * A string representing a value in the
+     * PowerSupplyProperties_BatteryState enumeration.
+     */
+    batteryState: {
+      type: String,
+      observer: 'batteryStateChanged',
+    },
+
+    /**
+     * An array representing the battery state options.
+     * The names are ordered based on the
+     * PowerSupplyProperties_BatteryState enumeration. These values must be
+     * in sync.
+     */
+    batteryStateOptions: {
+      type: Array,
+      value: function() { return ['Full', 'Charging', 'Disharging',
+      'Not Present']; },

[michaelpg, 2015/07/30 03:02:09]

nit: indent (preferably to align with 'Full')

[mozartalouis, 2015/07/30 21:18:18]

Done.

+    },
+
+    /**
+     * A string representing a value in the
      * PowerSupplyProperties_ExternalPower enumeration.
      */
     externalPower: {
       type: String,
+      observer: 'externalPowerChanged',
     },
 
     /**
-      * An array representing the external power options.
-      * The names are ordered based on the
-      * PowerSupplyProperties_ExternalPower enumeration. These values must be
-      * in sync.
-      */
+     * An array representing the external power options.
+     * The names are ordered based on the
+     * PowerSupplyProperties_ExternalPower enumeration. These values must be
+     * in sync.
+     */
     externalPowerOptions: {
       type: Array,
       value: function() { return ['AC', 'USB (Low Power)', 'Disconnected']; }
     },
 
     /**
      * A string representing the time left until the battery is discharged.
      */
     timeUntilEmpty: {
       type: String,
+      observer: 'timeUntilEmptyChanged',
     },
 
     /**
      * A string representing the time left until the battery is at 100%.
      */
     timeUntilFull: {
       type: String,
+      observer: 'timeUntilFullChanged',
     },
 
     /**
      * The title for the settings section.
      */
     title: {
       type: String,
     },
   },
 
   ready: function() {
     this.title = 'Power Settings';
   },
 
-  observers: [
-    'batteryPercentChanged(batteryPercent)',
-    'externalPowerChanged(externalPower)',
-    'timeUntilEmptyChanged(timeUntilEmpty)',
-    'timeUntilFullChanged(timeUntilFull)',
-  ],
-
-  batteryPercentChanged: function(percent) {
+  batteryPercentChanged: function(percent, oldPercent) {
+    if (oldPercent != undefined)
     chrome.send('updateBatteryPercent', [parseInt(percent)]);

[michaelpg, 2015/07/30 03:02:09]

indent

   },
 
-  externalPowerChanged: function(source) {
-    var index = -1;
-
-    // Find the index of the selected power source.
-    for (var i = 0; i < this.externalPowerOptions.length; i++) {
-      if (this.externalPowerOptions[i] == source) {
-        index = i;
-        break;
-      }
+  batteryStateChanged: function(state, oldState) {
+    // Find the index of the selected battery state.
+    if (oldState != undefined) {

[michaelpg, 2015/07/30 03:02:09]

This check is to ignore default values set by paper elements, right? Please be
sure to test that each of these properties actually gets set on load (as opposed
to being set by updatePowerProperties).

For example, checking "oldState != undefined" is unnecessary if a
<paper-radio-group> starts out as selected == undefined, which (at first glance)
is what it looks like.

[mozartalouis, 2015/07/30 21:18:18]

Done.

+      var index = this.batteryStateOptions.indexOf(state);
+      if (index >= 0)
+       chrome.send('updateBatteryState', [index]);
     }
-
-    if (index >= 0)
-      chrome.send('updateExternalPower', [index]);
   },
 
-  timeUntilEmptyChanged: function(time) {
-    chrome.send('updateTimeToEmpty', [parseInt(time)]);
+  externalPowerChanged: function(source, oldSource) {
+    // Find the index of the selected power source.
+    if (oldSource != undefined) {
+      var index = this.externalPowerOptions.indexOf(source);
+      if (index >= 0)
+        chrome.send('updateExternalPower', [index]);
+    }
   },
 
-  timeUntilFullChanged: function(time) {
-    chrome.send('updateTimeToFull', [parseInt(time)]);
+  timeUntilEmptyChanged: function(time, oldTime) {
+    if (oldTime != undefined)
+      chrome.send('updateTimeToEmpty', [parseInt(time)]);
   },
 
-  updatePowerProperties: function(percent, external_power, empty, full) {
-    this.batteryPercent = percent;
-    this.externalPower = this.externalPowerOptions[external_power];
-    this.timeUntilEmpty = empty;
-    this.timeUntilFull = full;
+  timeUntilFullChanged: function(time, oldTime) {
+    if (oldTime != undefined)
+      chrome.send('updateTimeToFull', [parseInt(time)]);
+  },
+
+  updatePowerProperties: function(power_properties) {
+    this.batteryPercent = power_properties.battery_percent;
+    this.batteryState =
+    this.batteryStateOptions[power_properties.battery_state];

[michaelpg, 2015/07/30 03:02:09]

indent 4 spaces

[mozartalouis, 2015/07/30 21:18:18]

Done.

+    this.externalPower =
+    this.externalPowerOptions[power_properties.external_power];

[michaelpg, 2015/07/30 03:02:09]

same

[mozartalouis, 2015/07/30 21:18:18]

Done.

+    this.timeUntilEmpty = power_properties.battery_time_to_empty_sec;
+    this.timeUntilFull = power_properties.battery_time_to_full_sec;
   }
 });