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

chrome/browser/chromeos/login/session/chrome_session_manager.cc

Index: chrome/browser/chromeos/login/session/chrome_session_manager.cc
diff --git a/chrome/browser/chromeos/login/session/chrome_session_manager.cc b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
index 34258c11804c3ccc8825247851d93856d7f266fe..3500807e682e37d4131899a56f95c724ae6e1eed 100644
--- a/chrome/browser/chromeos/login/session/chrome_session_manager.cc
+++ b/chrome/browser/chromeos/login/session/chrome_session_manager.cc
@@ -44,8 +44,8 @@ ChromeSessionManager::CreateSessionManager(
   bool force_login_screen_in_test =
       parsed_command_line.HasSwitch(switches::kForceLoginManagerInTests);
 
-  std::string login_user_id =
-      parsed_command_line.GetSwitchValueASCII(switches::kLoginUser);
+  const user_manager::UserID login_user_id =

[Denis Kuznetsov (DE-MUC), 2015/06/10 16:50:45]

auto

+      user_manager::UserID::FromUserEmail(parsed_command_line.GetSwitchValueASCII(switches::kLoginUser));
 
   KioskAppManager::RemoveObsoleteCryptohomes();
 
@@ -59,7 +59,7 @@ ChromeSessionManager::CreateSessionManager(
     return scoped_ptr<session_manager::SessionManager>(
         new ChromeSessionManager(new LoginOobeSessionManagerDelegate()));
   } else if (!base::SysInfo::IsRunningOnChromeOS() &&
-             login_user_id == login::kStubUser) {
+             login_user_id == login::GetStubUserID()) {
     VLOG(1) << "Starting Chrome with StubLoginSessionManagerDelegate";
     return scoped_ptr<session_manager::SessionManager>(new ChromeSessionManager(
         new StubLoginSessionManagerDelegate(profile, login_user_id)));