ChromeOS: implement per-user time zone preferences.

chrome/browser/chromeos/settings/system_settings_provider.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/chromeos/settings/system_settings_provider.h"
 
 #include "base/strings/string16.h"
 #include "base/time/time.h"
 #include "base/values.h"
+#include "chrome/browser/chromeos/system/timezone_util.h"
 #include "chromeos/login/login_state.h"
 #include "chromeos/settings/cros_settings_names.h"
 
 namespace chromeos {
 
 SystemSettingsProvider::SystemSettingsProvider(
     const NotifyObserversCallback& notify_cb)
     : CrosSettingsProvider(notify_cb) {
   system::TimezoneSettings *timezone_settings =
       system::TimezoneSettings::GetInstance();
   timezone_settings->AddObserver(this);
   timezone_value_.reset(
       new base::Value(timezone_settings->GetCurrentTimezoneID()));
+  per_user_timezone_enabled_value_.reset(
+      new base::Value(system::PerUserTimezoneEnabled()));
 }
 
 SystemSettingsProvider::~SystemSettingsProvider() {
   system::TimezoneSettings::GetInstance()->RemoveObserver(this);
 }
 
 void SystemSettingsProvider::DoSet(const std::string& path,
                                    const base::Value& in_value) {
   // Only non-guest users can change the time zone.
   if (LoginState::Get()->IsGuestSessionUser() ||
       LoginState::Get()->IsPublicSessionUser()) {
     return;
   }
 
   if (path == kSystemTimezone) {
     base::string16 timezone_id;
     if (!in_value.GetAsString(&timezone_id))
       return;
     // This will call TimezoneChanged.
     system::TimezoneSettings::GetInstance()->SetTimezoneFromID(timezone_id);
   }
+  // kPerUserTimezoneEnabled is read-only.
 }
 
 const base::Value* SystemSettingsProvider::Get(const std::string& path) const {
   if (path == kSystemTimezone)
     return timezone_value_.get();
+
+  if (path == kPerUserTimezoneEnabled)
+    return per_user_timezone_enabled_value_.get();
+
   return NULL;
 }
 
 // The timezone is always trusted.
 CrosSettingsProvider::TrustedStatus
     SystemSettingsProvider::PrepareTrustedValues(const base::Closure& cb) {
   return TRUSTED;
 }
 
 bool SystemSettingsProvider::HandlesSetting(const std::string& path) const {
-  return path == kSystemTimezone;
+  return path == kSystemTimezone || path == kPerUserTimezoneEnabled;
 }
 
 void SystemSettingsProvider::TimezoneChanged(const icu::TimeZone& timezone) {
   // Fires system setting change notification.
   timezone_value_.reset(
       new base::Value(system::TimezoneSettings::GetTimezoneID(timezone)));
   NotifyObservers(kSystemTimezone);
 }
 
 }  // namespace chromeos