ChromeOS: implement per-user time zone preferences.

chrome/browser/resources/settings/date_time_page/date_time_page.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.
 
 /**
  * @fileoverview
  * 'settings-date-time-page' is the settings page containing date and time
  * settings.
  */
 
@@ skipping 69 matching lines @@
 
     /**
      * Whether date and time are settable. Normally the date and time are forced
      * by network time, so default to false to initially hide the button.
      * @private
      */
     canSetDateTime_: {
       type: Boolean,
       value: false,
     },
+
+    /**
+     * Boolean flag indicatined whether per-user timezone option is enabled.

[michaelpg, 2017/05/30 22:21:23]

"indicating"

[Alexander Alekseev, 2017/07/06 06:30:29]

Done.

+     * @private
+     */
+    perUserTimezoneEnabled_: {
+      type: Boolean,
+      value: function() {
+        return loadTimeData.getBoolean('perUserTimezoneEnabled');
+      },
+    },
   },
 
+  // We need two separate observers, because prefs.settings.timezone.value is
+  // undefined when per-user timezone option is disabled, so we cannot combine
+  // all three inputs in a single observer.
   observers: [
     'maybeGetTimeZoneList_(' +
+        'prefs.settings.timezone.value, timeZoneAutoDetect_)',
+    'maybeGetTimeZoneList_(' +
         'prefs.cros.system.timezone.value, timeZoneAutoDetect_)',
   ],

[stevenjb, 2017/05/30 16:47:18]

This is much cleaner, thanks!

[Alexander Alekseev, 2017/07/06 06:30:29]

Done.

 
   /** @override */
   attached: function() {
     this.addWebUIListener(
         'time-zone-auto-detect-policy',
         this.onTimeZoneAutoDetectPolicyChanged_.bind(this));
     this.addWebUIListener(
         'can-set-date-time-changed', this.onCanSetDateTimeChanged_.bind(this));
 
     chrome.send('dateTimePageReady');
@@ skipping 69 matching lines @@
   /**
    * Fetches the list of time zones if necessary.
    * @private
    */
   maybeGetTimeZoneList_: function() {
     // Only fetch the list once.
     if (this.timeZoneList_.length > 1 || !CrSettingsPrefs.isInitialized)
       return;
 
     // If auto-detect is enabled, we only need the current time zone.
-    if (this.timeZoneAutoDetect_ &&
-        this.getPref('cros.system.timezone').value ==
-            this.timeZoneList_[0].value) {
-      return;
+    if (this.perUserTimezoneEnabled_) {

[michaelpg, 2017/05/30 22:21:23]

optional: use the "if" described in the comment.

if (this.timeZoneAutoDetect_) {
  if (this.perUserTimezoneEnabled_) ...

^ the reasoning is clearer that way IMO

Or, just use a ternary for the pref name depending on the value of
perUserTimezoneEnabled_?

[Alexander Alekseev, 2017/07/06 06:30:29]

Done.

+      if (this.timeZoneAutoDetect_ &&
+          this.getPref('settings.timezone').value ==
+              this.timeZoneList_[0].value) {
+        return;
+      }
+    } else {
+      if (this.timeZoneAutoDetect_ &&
+          this.getPref('cros.system.timezone').value ==
+              this.timeZoneList_[0].value) {
+        return;
+      }
     }
 
     cr.sendWithPromise('getTimeZones').then(this.setTimeZoneList_.bind(this));
   },
 
   /**
    * Converts the C++ response into an array of menu options.
    * @param {!Array<!Array<string>>} timeZones C++ time zones response.
    * @private
    */
   setTimeZoneList_: function(timeZones) {
     this.timeZoneList_ = timeZones.map(function(timeZonePair) {
       return {
         name: timeZonePair[1],
         value: timeZonePair[0],
       };
     });
   },
+
+  /**
+   * Computes visibility of user timezone preference.
+   * @param prefUserTimezone Object pref.settings.timezone
+   * @param prefResolveValue Boolean
+   *     prefs.settings.resolve_timezone_by_geolocation.value
+   * @private
+   */
+  isUserTimeZoneSelectorHidden_: function(prefUserTimezone, prefResolveValue) {
+    return (prefUserTimezone && prefUserTimezone.controlledBy != null) ||
+        (prefResolveValue == true);
+  },
 });