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 73 matching lines @@
      * @private
      */
     canSetDateTime_: {
       type: Boolean,
       value: false,
     },
   },
 
   observers: [
     'maybeGetTimeZoneList_(' +
-        'prefs.cros.system.timezone.value, timeZoneAutoDetect_)',
+        'prefs.settings.timezone.value, timeZoneAutoDetect_)',
+    'onPerUserTimezoneEnabledChanged_(' +
+        'prefs.cros.flags.per_user_timezone_enabled.value)',
   ],
 
+  // True if !prefs.cros.flags.per_user_timezone_enabled.value has been
+  // acknowledged.
+  nonPerUserTimezoneSeen_: false,
+
   /** @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');
     this.maybeGetTimeZoneList_();
@@ skipping 68 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;
+    var pref = this.getPref('cros.flags.per_user_timezone_enabled');
+    if (pref && pref.value) {
+      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);
+  },
+
+  /**
+   * Observer of this.prefs.cros.flags.per_user_timezone_enabled.value .
+   * If it becomes disabled, adds legacy observer.
+   * @private
+   */
+  onPerUserTimezoneEnabledChanged_: function() {
+    if (this.nonPerUserTimezoneSeen_)
+      return;
+
+    var pref = this.getPref('cros.flags.per_user_timezone_enabled');
+    if (!pref || !pref.value) {
+      this.nonPerUserTimezoneSeen_ = true;
+      // This is polymer private API, but we could probably remove this method
+      // before switching to polymer 2.0 .
+      this.get('_addComplexObserverEffect').call(this,
+          'maybeGetTimeZoneList_(' +
+          'prefs.cros.system.timezone.value, timeZoneAutoDetect_)');
+    }
+  },
 });