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

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index dd2b7015d23b54dfeec4e3254c2ffc82bee496fa..31fe77657b6bfb389e9b33f4069fc7ebc2c9135f 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -177,12 +177,12 @@ std::string GetNetworkName(const std::string& service_path) {
 }
 
 static bool SetUserInputMethodImpl(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& user_input_method,
     input_method::InputMethodManager::State* ime_state) {
   if (!chromeos::input_method::InputMethodManager::Get()->IsLoginKeyboard(
           user_input_method)) {
-    LOG(WARNING) << "SetUserInputMethod('" << username
+    LOG(WARNING) << "SetUserInputMethod('" << user_id.GetUserEmail()
                  << "'): stored user LRU input method '" << user_input_method
                  << "' is no longer Full Latin Keyboard Language"
                  << " (entry dropped). Use hardware default instead.";
@@ -192,14 +192,14 @@ static bool SetUserInputMethodImpl(
 
     base::DictionaryValue* const users_lru_input_methods = updater.Get();
     if (users_lru_input_methods != NULL) {
-      users_lru_input_methods->SetStringWithoutPathExpansion(username, "");
+      users_lru_input_methods->SetStringWithoutPathExpansion(user_id.GetUserEmail(), "");
     }
     return false;
   }
 
   if (!Contains(ime_state->GetActiveInputMethodIds(), user_input_method)) {
     if (!ime_state->EnableInputMethod(user_input_method)) {
-      DLOG(ERROR) << "SigninScreenHandler::SetUserInputMethod('" << username
+      DLOG(ERROR) << "SigninScreenHandler::SetUserInputMethod('" << user_id.GetUserEmail()
                   << "'): user input method '" << user_input_method
                   << "' is not enabled and enabling failed (ignored!).";
     }
@@ -297,27 +297,27 @@ SigninScreenHandler::~SigninScreenHandler() {
     max_mode_delegate_.reset(NULL);
   }
   GetScreenlockBridgeInstance()->SetLockHandler(NULL);
-  GetScreenlockBridgeInstance()->SetFocusedUser("");
+  GetScreenlockBridgeInstance()->SetFocusedUser(user_manager::UserID(std::string(), std::string()));
 }
 
 // static
 std::string SigninScreenHandler::GetUserLRUInputMethod(
-    const std::string& username) {
+    const user_manager::UserID& user_id) {
   PrefService* const local_state = g_browser_process->local_state();
   const base::DictionaryValue* users_lru_input_methods =
       local_state->GetDictionary(prefs::kUsersLRUInputMethod);
 
   if (!users_lru_input_methods) {
-    DLOG(WARNING) << "GetUserLRUInputMethod('" << username
+    DLOG(WARNING) << "GetUserLRUInputMethod('" << user_id.GetUserEmail()
                   << "'): no kUsersLRUInputMethod";
     return std::string();
   }
 
   std::string input_method;
 
-  if (!users_lru_input_methods->GetStringWithoutPathExpansion(username,
+  if (!users_lru_input_methods->GetStringWithoutPathExpansion(user_id.GetUserEmail(),
                                                               &input_method)) {
-    DVLOG(0) << "GetUserLRUInputMethod('" << username
+    DVLOG(0) << "GetUserLRUInputMethod('" << user_id.GetUserEmail()
              << "'): no input method for this user";
     return std::string();
   }
@@ -328,20 +328,20 @@ std::string SigninScreenHandler::GetUserLRUInputMethod(
 // static
 // Update keyboard layout to least recently used by the user.
 void SigninScreenHandler::SetUserInputMethod(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     input_method::InputMethodManager::State* ime_state) {
   bool succeed = false;
 
-  const std::string input_method = GetUserLRUInputMethod(username);
+  const std::string input_method = GetUserLRUInputMethod(user_id);
 
   if (!input_method.empty())
-    succeed = SetUserInputMethodImpl(username, input_method, ime_state);
+    succeed = SetUserInputMethodImpl(user_id, input_method, ime_state);
 
   // This is also a case when LRU layout is set only for a few local users,
   // thus others need to be switched to default locale.
   // Otherwise they will end up using another user's locale to log in.
   if (!succeed) {
-    DVLOG(0) << "SetUserInputMethod('" << username
+    DVLOG(0) << "SetUserInputMethod('" << user_id.GetUserEmail()
              << "'): failed to set user layout. Switching to default.";
 
     ime_state->SetInputMethodLoginDefault();
@@ -886,15 +886,15 @@ void SigninScreenHandler::RefocusCurrentPod() {
   core_oobe_actor_->RefocusCurrentPod();
 }
 
-void SigninScreenHandler::OnUserRemoved(const std::string& username) {
-  CallJS("login.AccountPickerScreen.removeUser", username);
+void SigninScreenHandler::OnUserRemoved(const user_manager::UserID& user_id) {
+  CallJS("login.AccountPickerScreen.removeUser", user_id.GetUserEmail());
   if (delegate_->GetUsers().empty())
     OnShowAddUser();
 }
 
 void SigninScreenHandler::OnUserImageChanged(const user_manager::User& user) {
   if (page_is_ready())
-    CallJS("login.AccountPickerScreen.updateUserImage", user.email());
+    CallJS("login.AccountPickerScreen.updateUserImage", user.GetUserID().GetUserEmail());
 }
 
 void SigninScreenHandler::OnPreferencesChanged() {
@@ -939,29 +939,29 @@ void SigninScreenHandler::ShowErrorScreen(LoginDisplay::SigninError error_id) {
   }
 }
 
-void SigninScreenHandler::ShowSigninUI(const std::string& email) {
-  core_oobe_actor_->ShowSignInUI(email);
+void SigninScreenHandler::ShowSigninUI(const user_manager::UserID& user_id) {
+  core_oobe_actor_->ShowSignInUI(user_id);
 }
 
-void SigninScreenHandler::ShowGaiaPasswordChanged(const std::string& username) {
-  gaia_screen_handler_->PasswordChangedFor(username);
-  gaia_screen_handler_->PopulateEmail(username);
-  core_oobe_actor_->ShowSignInUI(username);
-  CallJS("login.setAuthType", username,
+void SigninScreenHandler::ShowGaiaPasswordChanged(const user_manager::UserID& user_id) {
+  gaia_screen_handler_->PasswordChangedFor(user_id);
+  gaia_screen_handler_->PopulateEmail(user_id.GetUserEmail());
+  core_oobe_actor_->ShowSignInUI(user_id);
+  CallJS("login.setAuthType", user_id.GetUserEmail(),
          static_cast<int>(UserSelectionScreen::ONLINE_SIGN_IN),
          base::StringValue(""));
 }
 
 void SigninScreenHandler::ShowPasswordChangedDialog(bool show_password_error,
-                                                    const std::string& email) {
-  core_oobe_actor_->ShowPasswordChangedScreen(show_password_error, email);
+                                                    const user_manager::UserID& user_id) {
+  core_oobe_actor_->ShowPasswordChangedScreen(show_password_error, user_id);
 }
 
 void SigninScreenHandler::ShowSigninScreenForCreds(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& password) {
   DCHECK(gaia_screen_handler_);
-  gaia_screen_handler_->ShowSigninScreenForCreds(username, password);
+  gaia_screen_handler_->ShowSigninScreenForCreds(user_id, password);
 }
 
 void SigninScreenHandler::ShowWhitelistCheckFailedError() {
@@ -1029,13 +1029,13 @@ void SigninScreenHandler::HandleAuthenticateUser(const std::string& username,
                                                  const std::string& password) {
   if (!delegate_)
     return;
-  UserContext user_context(gaia::SanitizeEmail(username));
+  UserContext user_context(user_manager::UserID::FromUserEmail(gaia::SanitizeEmail(username)));
   user_context.SetKey(Key(password));
   delegate_->Login(user_context, SigninSpecifics());
 }
 
 void SigninScreenHandler::HandleLaunchIncognito() {
-  UserContext context(user_manager::USER_TYPE_GUEST, std::string());
+  UserContext context(user_manager::USER_TYPE_GUEST, user_manager::UserID(std::string(), std::string()));
   if (delegate_)
     delegate_->Login(context, SigninSpecifics());
 }
@@ -1050,12 +1050,14 @@ void SigninScreenHandler::HandleShowSupervisedUserCreationScreen() {
 }
 
 void SigninScreenHandler::HandleLaunchPublicSession(
-    const std::string& user_id,
+    const std::string& user_id_str,
     const std::string& locale,
     const std::string& input_method) {
   if (!delegate_)
     return;
 
+  const user_manager::UserID user_id(user_manager::UserID::FromUserEmail(user_id_str));
+
   UserContext context(user_manager::USER_TYPE_PUBLIC_ACCOUNT, user_id);
   context.SetPublicSessionLocale(locale),
   context.SetPublicSessionInputMethod(input_method);
@@ -1083,7 +1085,7 @@ void SigninScreenHandler::HandleShutdownSystem() {
 
 void SigninScreenHandler::HandleLoadWallpaper(const std::string& email) {
   if (delegate_)
-    delegate_->LoadWallpaper(email);
+    delegate_->LoadWallpaper(user_manager::UserID::FromUserEmail(email));
 }
 
 void SigninScreenHandler::HandleRebootSystem() {
@@ -1093,7 +1095,7 @@ void SigninScreenHandler::HandleRebootSystem() {
 void SigninScreenHandler::HandleRemoveUser(const std::string& email) {
   if (!delegate_)
     return;
-  delegate_->RemoveUser(email);
+  delegate_->RemoveUser(user_manager::UserID::FromUserEmail(email));
   UpdateAddButtonStatus();
 }
 
@@ -1108,7 +1110,7 @@ void SigninScreenHandler::HandleShowAddUser(const base::ListValue* args) {
     args->GetString(0, &email);
   gaia_screen_handler_->PopulateEmail(email);
   if (!email.empty())
-    SendReauthReason(email);
+    SendReauthReason(user_manager::UserID::FromUserEmail(email));
   OnShowAddUser();
 }
 
@@ -1214,9 +1216,9 @@ void SigninScreenHandler::HandleLoginVisible(const std::string& source) {
 }
 
 void SigninScreenHandler::HandleCancelPasswordChangedFlow(
-    const std::string& user_id) {
-  if (!user_id.empty())
-    RecordReauthReason(user_id, ReauthReason::PASSWORD_UPDATE_SKIPPED);
+    const std::string& user_id_str) {
+  if (!user_id_str.empty())
+    RecordReauthReason(user_manager::UserID::FromUserEmail(user_id_str), ReauthReason::PASSWORD_UPDATE_SKIPPED);
   gaia_screen_handler_->StartClearingCookies(
       base::Bind(&SigninScreenHandler::CancelPasswordChangedFlowInternal,
                  weak_factory_.GetWeakPtr()));
@@ -1278,7 +1280,8 @@ void SigninScreenHandler::HandleUpdateOfflineLogin(bool offline_login_active) {
   offline_login_active_ = offline_login_active;
 }
 
-void SigninScreenHandler::HandleFocusPod(const std::string& user_id) {
+void SigninScreenHandler::HandleFocusPod(const std::string& user_id_str) {
+  const user_manager::UserID user_id(user_manager::UserID::FromUserEmail(user_id_str));
   SetUserInputMethod(user_id, ime_state_.get());
   WallpaperManager::Get()->SetUserWallpaperDelayed(user_id);
   GetScreenlockBridgeInstance()->SetFocusedUser(user_id);
@@ -1289,29 +1292,30 @@ void SigninScreenHandler::HandleFocusPod(const std::string& user_id) {
 }
 
 void SigninScreenHandler::HandleGetPublicSessionKeyboardLayouts(
-    const std::string& user_id,
+    const std::string& user_id_str,
     const std::string& locale) {
   GetKeyboardLayoutsForLocale(
       base::Bind(&SigninScreenHandler::SendPublicSessionKeyboardLayouts,
                  weak_factory_.GetWeakPtr(),
-                 user_id,
+                 user_manager::UserID::FromUserEmail(user_id_str),
                  locale),
       locale);
 }
 
 void SigninScreenHandler::SendPublicSessionKeyboardLayouts(
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     const std::string& locale,
     scoped_ptr<base::ListValue> keyboard_layouts) {
   CallJS("login.AccountPickerScreen.setPublicSessionKeyboardLayouts",
-         user_id,
+         user_id.GetUserEmail(),
          locale,
          *keyboard_layouts);
 }
 
 void SigninScreenHandler::HandleLaunchKioskApp(const std::string& app_id,
                                                bool diagnostic_mode) {
-  UserContext context(user_manager::USER_TYPE_KIOSK_APP, app_id);
+  const user_manager::UserID app_user_id(user_manager::UserID::FromUserEmail(app_id));
+  UserContext context(user_manager::USER_TYPE_KIOSK_APP, app_user_id);
   SigninSpecifics specifics;
   specifics.kiosk_diagnostic_mode = diagnostic_mode;
   if (delegate_)
@@ -1352,7 +1356,7 @@ void SigninScreenHandler::HandleFirstIncorrectPasswordAttempt(
 
 void SigninScreenHandler::HandleMaxIncorrectPasswordAttempts(
     const std::string& email) {
-  RecordReauthReason(email, ReauthReason::INCORRECT_PASSWORD_ENTERED);
+  RecordReauthReason(user_manager::UserID::FromUserEmail(email), ReauthReason::INCORRECT_PASSWORD_ENTERED);
 }
 
 bool SigninScreenHandler::AllWhitelistedUsersPresent() {
@@ -1373,7 +1377,7 @@ bool SigninScreenHandler::AllWhitelistedUsersPresent() {
     std::string whitelisted_user;
     // NB: Wildcards in the whitelist are also detected as not present here.
     if (!whitelist->GetString(i, &whitelisted_user) ||
-        !user_manager->IsKnownUser(whitelisted_user)) {
+        !user_manager->IsKnownUser(user_manager::UserID::FromUserEmail(whitelisted_user))) {
       return false;
     }
   }