This CL replaces e-mail with AccountId on user selection screen.

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 1f05411ec0dd3342a96b0f9468a9157cdc7a9d87..1d841777bc160e498844ba581cdb0a6326b7a4a5 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -874,7 +874,8 @@ void SigninScreenHandler::OnUserRemoved(const std::string& username,
 
 void SigninScreenHandler::OnUserImageChanged(const user_manager::User& user) {
   if (page_is_ready())
-    CallJS("login.AccountPickerScreen.updateUserImage", user.email());
+    CallJS("login.AccountPickerScreen.updateUserImage",
+           user.GetAccountId().Serialize());
 }
 
 void SigninScreenHandler::OnPreferencesChanged() {
@@ -988,12 +989,22 @@ void SigninScreenHandler::UpdateAddButtonStatus() {
          AllWhitelistedUsersPresent());
 }
 
-void SigninScreenHandler::HandleAuthenticateUser(const std::string& username,
+void SigninScreenHandler::HandleAuthenticateUser(const std::string& user_id,
                                                  const std::string& password) {
   if (!delegate_)
     return;
-  UserContext user_context(
-      AccountId::FromUserEmail(gaia::SanitizeEmail(username)));
+  AccountId account_id(EmptyAccountId());

[dzhioev (left Google), 2015/11/12 00:46:24]

Why default constructor of AccountId doesn't produse 'empty account id'?

[Alexander Alekseev, 2015/11/12 06:53:04]

To force manual construction. We can change this after migration is done, but
for now it is dangerous.

+  const bool status = AccountId::Deserialize(user_id, &account_id);

[stevenjb, 2015/11/11 20:39:23]

"user_id" does not imply a JSON dictionary. Use something like 'account_json' or
'serialized_user'.

[Alexander Alekseev, 2015/11/12 06:53:04]

Done.

+  // TODO(alemate): this is used also for offline Gaia.
+  // Add DCHECK() once migrated.
+  if (!status) {
+    LOG(WARNING) << "Failed to parse user_id='" << user_id << "'";
+    account_id = AccountId::FromUserEmail(user_id);
+  }
+  DCHECK_EQ(account_id.GetUserEmail(),
+            gaia::SanitizeEmail(account_id.GetUserEmail()));
+
+  UserContext user_context(account_id);
   user_context.SetKey(Key(password));
   delegate_->Login(user_context, SigninSpecifics());
 }
@@ -1020,7 +1031,11 @@ void SigninScreenHandler::HandleLaunchPublicSession(
   if (!delegate_)
     return;
 
-  UserContext context(user_manager::USER_TYPE_PUBLIC_ACCOUNT, user_id);
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(user_id, &account_id);
+  DCHECK(status) << "Failed to parse user_id='" << user_id << "'";
+  UserContext context(user_manager::USER_TYPE_PUBLIC_ACCOUNT,
+                      account_id.GetUserEmail());
   context.SetPublicSessionLocale(locale),
   context.SetPublicSessionInputMethod(input_method);
   delegate_->Login(context, SigninSpecifics());
@@ -1175,9 +1190,12 @@ void SigninScreenHandler::HandleLoginVisible(const std::string& source) {
 
 void SigninScreenHandler::HandleCancelPasswordChangedFlow(
     const std::string& user_id) {
-  if (!user_id.empty())
-    RecordReauthReason(AccountId::FromUserEmail(user_id),
-                       ReauthReason::PASSWORD_UPDATE_SKIPPED);
+  if (!user_id.empty()) {
+    AccountId account_id(EmptyAccountId());
+    const bool status = AccountId::Deserialize(user_id, &account_id);
+    DCHECK(status) << "Failed to parse user_id='" << user_id << "'";
+    RecordReauthReason(account_id, ReauthReason::PASSWORD_UPDATE_SKIPPED);
+  }
   gaia_screen_handler_->StartClearingCookies(
       base::Bind(&SigninScreenHandler::CancelPasswordChangedFlowInternal,
                  weak_factory_.GetWeakPtr()));
@@ -1236,18 +1254,21 @@ void SigninScreenHandler::HandleShowLoadingTimeoutError() {
 }
 
 void SigninScreenHandler::HandleFocusPod(const std::string& user_id) {
-  SetUserInputMethod(user_id, ime_state_.get());
-  WallpaperManager::Get()->SetUserWallpaperDelayed(user_id);
-  proximity_auth::ScreenlockBridge::Get()->SetFocusedUser(user_id);
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(user_id, &account_id);
+  DCHECK(status) << "Failed to parse user_id='" << user_id << "'";
+  SetUserInputMethod(account_id.GetUserEmail(), ime_state_.get());
+  WallpaperManager::Get()->SetUserWallpaperDelayed(account_id.GetUserEmail());
+  proximity_auth::ScreenlockBridge::Get()->SetFocusedUser(
+      account_id.GetUserEmail());
   if (delegate_)
-    delegate_->CheckUserStatus(user_id);
+    delegate_->CheckUserStatus(account_id.GetUserEmail());
   if (!test_focus_pod_callback_.is_null())
     test_focus_pod_callback_.Run();
 
   bool use_24hour_clock = false;
   if (user_manager::UserManager::Get()->GetKnownUserBooleanPref(
-          AccountId::FromUserEmail(user_id), prefs::kUse24HourClock,
-          &use_24hour_clock)) {
+          account_id, prefs::kUse24HourClock, &use_24hour_clock)) {
     g_browser_process->platform_part()
         ->GetSystemClock()
         ->SetLastFocusedPodHourClockType(use_24hour_clock ? base::k24HourClock
@@ -1258,27 +1279,30 @@ void SigninScreenHandler::HandleFocusPod(const std::string& user_id) {
 void SigninScreenHandler::HandleGetPublicSessionKeyboardLayouts(
     const std::string& user_id,
     const std::string& locale) {
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(user_id, &account_id);
+  DCHECK(status) << "Failed to parse user_id='" << user_id << "'";
   GetKeyboardLayoutsForLocale(
       base::Bind(&SigninScreenHandler::SendPublicSessionKeyboardLayouts,
-                 weak_factory_.GetWeakPtr(),
-                 user_id,
-                 locale),
+                 weak_factory_.GetWeakPtr(), account_id, locale),
       locale);
 }
 
 void SigninScreenHandler::SendPublicSessionKeyboardLayouts(
-    const std::string& user_id,
+    const AccountId& account_id,
     const std::string& locale,
     scoped_ptr<base::ListValue> keyboard_layouts) {
   CallJS("login.AccountPickerScreen.setPublicSessionKeyboardLayouts",
-         user_id,
-         locale,
-         *keyboard_layouts);
+         account_id.Serialize(), locale, *keyboard_layouts);
 }
 
 void SigninScreenHandler::HandleLaunchKioskApp(const std::string& app_id,
                                                bool diagnostic_mode) {
-  UserContext context(user_manager::USER_TYPE_KIOSK_APP, app_id);
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(app_id, &account_id);
+  DCHECK(status) << "Failed to parse app_id='" << app_id << "'";
+  UserContext context(user_manager::USER_TYPE_KIOSK_APP,
+                      account_id.GetUserEmail());
   SigninSpecifics specifics;
   specifics.kiosk_diagnostic_mode = diagnostic_mode;
   if (delegate_)
@@ -1309,7 +1333,7 @@ void SigninScreenHandler::HandleLogRemoveUserWarningShown() {
 }
 
 void SigninScreenHandler::HandleFirstIncorrectPasswordAttempt(
-    const std::string& email) {
+    const std::string& user_id) {
   // TODO(ginkage): Fix this case once crbug.com/469987 is ready.
   /*
     if (user_manager::UserManager::Get()->FindUsingSAML(email))
@@ -1318,9 +1342,11 @@ void SigninScreenHandler::HandleFirstIncorrectPasswordAttempt(
 }
 
 void SigninScreenHandler::HandleMaxIncorrectPasswordAttempts(
-    const std::string& email) {
-  RecordReauthReason(AccountId::FromUserEmail(email),
-                     ReauthReason::INCORRECT_PASSWORD_ENTERED);
+    const std::string& user_id) {
+  AccountId account_id(EmptyAccountId());
+  const bool status = AccountId::Deserialize(user_id, &account_id);
+  DCHECK(status) << "Failed to parse user_id='" << user_id << "'";
+  RecordReauthReason(account_id, ReauthReason::INCORRECT_PASSWORD_ENTERED);
 }
 
 bool SigninScreenHandler::AllWhitelistedUsersPresent() {