We should use UserID object to identify users instead of username.

chrome/browser/ui/ash/system_tray_delegate_chromeos.cc

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
index f4e1284145daa29df6ec5f3f7aee0a4f253b6661..4df46ad2907b8886af453c5969fa8d1418e861a9 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.cc
@@ -99,6 +99,7 @@
 #include "components/google/core/browser/google_util.h"
 #include "components/policy/core/common/cloud/cloud_policy_store.h"
 #include "components/user_manager/user.h"
+#include "components/user_manager/user_id.h"
 #include "components/user_manager/user_manager.h"
 #include "components/user_manager/user_type.h"
 #include "content/public/browser/notification_observer.h"
@@ -596,7 +597,7 @@ void SystemTrayDelegateChromeOS::ShowUserLogin() {
          it != logged_in_users.end();
          ++it) {
       show_intro &= !multi_user_util::GetProfileFromUserID(
-                         multi_user_util::GetUserIDFromEmail((*it)->email()))
+                         multi_user_util::GetUserIDFromEmail((*it)->GetUserID().GetUserEmail()))
                          ->GetPrefs()
                          ->GetBoolean(prefs::kMultiProfileNeverShowIntro);
       if (!show_intro)
@@ -838,7 +839,7 @@ bool SystemTrayDelegateChromeOS::IsSearchKeyMappedToCapsLock() {
 
 ash::tray::UserAccountsDelegate*
 SystemTrayDelegateChromeOS::GetUserAccountsDelegate(
-    const std::string& user_id) {
+    const user_manager::UserID& user_id) {
   if (!accounts_delegates_.contains(user_id)) {
     const user_manager::User* user =
         user_manager::UserManager::Get()->FindUser(user_id);
@@ -1350,12 +1351,12 @@ void SystemTrayDelegateChromeOS::OnStoreError(policy::CloudPolicyStore* store) {
 
 // Overridden from ash::SessionStateObserver
 void SystemTrayDelegateChromeOS::UserAddedToSession(
-    const std::string& user_id) {
+    const user_manager::UserID& user_id) {
   GetSystemTrayNotifier()->NotifyUserAddedToSession();
 }
 
 void SystemTrayDelegateChromeOS::ActiveUserChanged(
-    const std::string& /* user_id */) {
+    const user_manager::UserID& /* user_id */) {
   UpdateClockType();
 }