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

chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc

Index: chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
diff --git a/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc b/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
index 79687410e34c61230cb660958c6dfd10d947eee2..56a6d03393bd531f3307092e4734f2c9cfd526e3 100644
--- a/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
+++ b/chrome/browser/chromeos/policy/user_cloud_policy_manager_factory_chromeos.cc
@@ -136,16 +136,16 @@ scoped_ptr<UserCloudPolicyManagerChromeOS>
   // - For device-local accounts, policy is provided by
   //   |DeviceLocalAccountPolicyService|.
   // All other user types do not have user policy.
-  const std::string& username = user->email();
+  const user_manager::UserID& user_id = user->GetUserID();
   if (!user->HasGaiaAccount() ||
       user->IsSupervised() ||
-      BrowserPolicyConnector::IsNonEnterpriseUser(username)) {
+      BrowserPolicyConnector::IsNonEnterpriseUser(user_id)) {
     return scoped_ptr<UserCloudPolicyManagerChromeOS>();
   }
 
   policy::BrowserPolicyConnectorChromeOS* connector =
       g_browser_process->platform_part()->browser_policy_connector_chromeos();
-  UserAffiliation affiliation = connector->GetUserAffiliation(username);
+  UserAffiliation affiliation = connector->GetUserAffiliation(user_id);
   const bool is_affiliated_user = affiliation == USER_AFFILIATION_MANAGED;
   const bool is_browser_restart =
       command_line->HasSwitch(chromeos::switches::kLoginUser);
@@ -180,7 +180,7 @@ scoped_ptr<UserCloudPolicyManagerChromeOS>
           chromeos::DBusThreadManager::Get()->GetCryptohomeClient(),
           chromeos::DBusThreadManager::Get()->GetSessionManagerClient(),
           background_task_runner,
-          username, policy_key_dir, token_cache_file, policy_cache_file));
+          user_id, policy_key_dir, token_cache_file, policy_cache_file));
 
   scoped_refptr<base::SequencedTaskRunner> backend_task_runner =
       content::BrowserThread::GetBlockingPool()->GetSequencedTaskRunner(
@@ -210,9 +210,9 @@ scoped_ptr<UserCloudPolicyManagerChromeOS>
 
   bool wildcard_match = false;
   if (connector->IsEnterpriseManaged() &&
-      chromeos::CrosSettings::IsWhitelisted(username, &wildcard_match) &&
-      wildcard_match && !connector->IsNonEnterpriseUser(username)) {
-    manager->EnableWildcardLoginCheck(username);
+      chromeos::CrosSettings::IsWhitelisted(user_id, &wildcard_match) &&
+      wildcard_match && !connector->IsNonEnterpriseUser(user_id)) {
+    manager->EnableWildcardLoginCheck(user_id);
   }
 
   manager->Init(