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

chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc

 // Copyright 2014 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/policy/browser_policy_connector_chromeos.h"
 
 #include <string>
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
@@ skipping 254 matching lines @@
 
 EnrollmentConfig BrowserPolicyConnectorChromeOS::GetPrescribedEnrollmentConfig()
     const {
   if (device_cloud_policy_initializer_)
     return device_cloud_policy_initializer_->GetPrescribedEnrollmentConfig();
 
   return EnrollmentConfig();
 }
 
 UserAffiliation BrowserPolicyConnectorChromeOS::GetUserAffiliation(
-    const std::string& user_name) {
+    const user_manager::UserID& user_id) {
   // An empty username means incognito user in case of ChromiumOS and
   // no logged-in user in case of Chromium (SigninService). Many tests use
   // nonsense email addresses (e.g. 'test') so treat those as non-enterprise
   // users.
-  if (user_name.empty() || user_name.find('@') == std::string::npos)
+  if (user_id.GetUserEmail().empty() || user_id.GetUserEmail().find('@') == std::string::npos)
     return USER_AFFILIATION_NONE;
 
   if (install_attributes_ &&
-      (gaia::ExtractDomainName(gaia::CanonicalizeEmail(user_name)) ==
+      (gaia::ExtractDomainName(gaia::CanonicalizeEmail(user_id.GetUserEmail())) ==
            install_attributes_->GetDomain() ||
-       policy::IsDeviceLocalAccountUser(user_name, NULL))) {
+       policy::IsDeviceLocalAccountUser(user_id, NULL))) {
     return USER_AFFILIATION_MANAGED;
   }
 
   return USER_AFFILIATION_NONE;
 }
 
 void BrowserPolicyConnectorChromeOS::SetUserPolicyDelegate(
     ConfigurationPolicyProvider* user_policy_provider) {
   global_user_cloud_policy_provider_->SetDelegate(user_policy_provider);
 }
@@ skipping 74 matching lines @@
           consumer_device_management_service_.get(),
           GetBackgroundTaskRunner(),
           install_attributes_.get(),
           state_keys_broker_.get(),
           device_cloud_policy_manager_->device_store(),
           device_cloud_policy_manager_));
   device_cloud_policy_initializer_->Init();
 }
 
 }  // namespace policy