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

chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc

Index: chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
diff --git a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
index 20fdd78e8d435fccaeb0ae4fefbe0d16794675b4..ee5aa3375ca6054d698e35b89e9c917ae128d6d4 100644
--- a/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
+++ b/chrome/browser/chromeos/ownership/owner_settings_service_chromeos.cc
@@ -48,7 +48,7 @@ namespace chromeos {
 
 namespace {
 
-bool IsOwnerInTests(const std::string& user_id) {
+bool IsOwnerInTests(const user_manager::UserID& user_id) {
   if (user_id.empty() ||
       !base::CommandLine::ForCurrentProcess()->HasSwitch(
           ::switches::kTestType) ||
@@ -58,7 +58,7 @@ bool IsOwnerInTests(const std::string& user_id) {
   const base::Value* value = CrosSettings::Get()->GetPref(kDeviceOwner);
   if (!value || value->GetType() != base::Value::TYPE_STRING)
     return false;
-  return static_cast<const base::StringValue*>(value)->GetString() == user_id;
+  return static_cast<const base::StringValue*>(value)->GetString() == user_id.GetUserEmail();
 }
 
 void LoadPrivateKeyByPublicKey(
@@ -196,6 +196,7 @@ OwnerSettingsServiceChromeOS::OwnerSettingsServiceChromeOS(
     : ownership::OwnerSettingsService(owner_key_util),
       device_settings_service_(device_settings_service),
       profile_(profile),
+      user_id_(std::string(), std::string()),

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

EmptyUserId()

       waiting_for_profile_creation_(true),
       waiting_for_tpm_token_(true),
       has_pending_fixups_(false),
@@ -283,7 +284,7 @@ bool OwnerSettingsServiceChromeOS::Set(const std::string& setting,
   }
   UpdateDeviceSettings(setting, value, settings);
   em::PolicyData policy_data;
-  policy_data.set_username(user_id_);
+  policy_data.set_username(user_id_.GetUserEmail());
   CHECK(settings.SerializeToString(policy_data.mutable_policy_value()));
   FOR_EACH_OBSERVER(OwnerSettingsService::Observer, observers_,
                     OnTentativeChangesInPolicy(policy_data));
@@ -321,9 +322,9 @@ bool OwnerSettingsServiceChromeOS::CommitTentativeDeviceSettings(
     scoped_ptr<enterprise_management::PolicyData> policy) {
   if (!IsOwner() && !IsOwnerInTests(user_id_))
     return false;
-  if (policy->username() != user_id_) {
+  if (user_manager::UserID::FromUserEmail(policy->username()) != user_id_) {
     LOG(ERROR) << "Username mismatch: " << policy->username() << " vs. "
-               << user_id_;
+               << user_id_.GetUserEmail();
     return false;
   }
   tentative_settings_.reset(new em::ChromeDeviceSettingsProto);
@@ -424,7 +425,7 @@ void OwnerSettingsServiceChromeOS::IsOwnerForSafeModeAsync(
 
 // static
 scoped_ptr<em::PolicyData> OwnerSettingsServiceChromeOS::AssemblePolicy(
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const em::PolicyData* policy_data,
     bool apply_pending_management_settings,
     const ManagementSettings& pending_management_settings,
@@ -460,7 +461,7 @@ scoped_ptr<em::PolicyData> OwnerSettingsServiceChromeOS::AssemblePolicy(
   policy->set_policy_type(policy::dm_protocol::kChromeDevicePolicyType);
   policy->set_timestamp(
       (base::Time::Now() - base::Time::UnixEpoch()).InMilliseconds());
-  policy->set_username(user_id);
+  policy->set_username(user_id.GetUserEmail());
   if (policy_data->management_mode() == em::PolicyData::LOCAL_OWNER ||
       policy_data->management_mode() == em::PolicyData::CONSUMER_MANAGED) {
     FixupLocalOwnerPolicy(user_id, settings);
@@ -473,7 +474,7 @@ scoped_ptr<em::PolicyData> OwnerSettingsServiceChromeOS::AssemblePolicy(
 
 // static
 void OwnerSettingsServiceChromeOS::FixupLocalOwnerPolicy(
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     enterprise_management::ChromeDeviceSettingsProto* settings) {
   if (!settings->has_allow_new_users())
     settings->mutable_allow_new_users()->set_allow_new_users(true);
@@ -481,8 +482,8 @@ void OwnerSettingsServiceChromeOS::FixupLocalOwnerPolicy(
   em::UserWhitelistProto* whitelist_proto = settings->mutable_user_whitelist();
   if (whitelist_proto->user_whitelist().end() ==
       std::find(whitelist_proto->user_whitelist().begin(),
-                whitelist_proto->user_whitelist().end(), user_id)) {
-    whitelist_proto->add_user_whitelist(user_id);
+                whitelist_proto->user_whitelist().end(), user_id.GetUserEmail())) {
+    whitelist_proto->add_user_whitelist(user_id.GetUserEmail());
   }
 }
 
@@ -629,8 +630,10 @@ void OwnerSettingsServiceChromeOS::UpdateDeviceSettings(
            i != users->end();
            ++i) {
         std::string email;
-        if ((*i)->GetAsString(&email))
-          whitelist_proto->add_user_whitelist(email);
+        if ((*i)->GetAsString(&email)) {
+          const user_manager::UserID user_id(user_manager::UserID::FromUserEmail(email));
+          whitelist_proto->add_user_whitelist(user_id.GetUserEmail());
+        }
       }
     }
   } else if (path == kAccountsPrefEphemeralUsersEnabled) {
@@ -716,7 +719,7 @@ void OwnerSettingsServiceChromeOS::OnPostKeypairLoadedActions() {
 
   const user_manager::User* user =
       ProfileHelper::Get()->GetUserByProfile(profile_);
-  user_id_ = user ? user->GetUserID() : std::string();
+  user_id_ = user ? user->GetUserID() : user_manager::EmptyUserID();
 
   const bool is_owner = IsOwner() || IsOwnerInTests(user_id_);
   if (is_owner && device_settings_service_)