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

chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc

Index: chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc
diff --git a/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc b/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc
index 6058ba9260c3a08ca2a682694e19e4f172df1249..64735fd018c61cd0050c5b728bbc4fb1645c647f 100644
--- a/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc
+++ b/chrome/browser/chromeos/policy/browser_policy_connector_chromeos.cc
@@ -272,18 +272,18 @@ EnrollmentConfig BrowserPolicyConnectorChromeOS::GetPrescribedEnrollmentConfig()
 }
 
 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;
   }