ChromeOS: implement per-user time zone preferences.

chrome/browser/chromeos/login/wizard_controller.cc

Index: chrome/browser/chromeos/login/wizard_controller.cc
diff --git a/chrome/browser/chromeos/login/wizard_controller.cc b/chrome/browser/chromeos/login/wizard_controller.cc
index 84a770db3f4eaa288b1cf94418e4f0c1ddd248f3..6ae7af08ab85f3cda562614b4e5fd1a505519450 100644
--- a/chrome/browser/chromeos/login/wizard_controller.cc
+++ b/chrome/browser/chromeos/login/wizard_controller.cc
@@ -62,6 +62,7 @@
 #include "chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "chrome/browser/chromeos/system/device_disabling_manager.h"
+#include "chrome/browser/chromeos/system/timezone_util.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/metrics/metrics_reporting_state.h"
 #include "chrome/browser/profiles/profile.h"
@@ -1427,9 +1428,8 @@ void WizardController::OnTimezoneResolved(
   if (!timezone->timeZoneId.empty()) {
     VLOG(1) << "Resolve TimeZone: setting timezone to '" << timezone->timeZoneId
             << "'";
-
-    system::TimezoneSettings::GetInstance()->SetTimezoneFromID(
-        base::UTF8ToUTF16(timezone->timeZoneId));
+    chromeos::system::SetSigninScreenTimezone(timezone->timeZoneId,
+                                              true /* set_system_timezone */);
   }
 }