ChromeOS cryptohome should be able to use gaia id as user identifier.

chrome/browser/chromeos/login/existing_user_controller.cc

 // Copyright (c) 2012 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/login/existing_user_controller.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 721 matching lines @@
 }
 
 bool ExistingUserController::password_changed() const {
   if (login_performer_)
     return login_performer_->password_changed();
 
   return password_changed_;
 }
 
 void ExistingUserController::LoginAsGuest() {
-  PerformPreLoginActions(UserContext(user_manager::USER_TYPE_GUEST,
-                                     login::GuestAccountId().GetUserEmail()));
+  PerformPreLoginActions(
+      UserContext(user_manager::USER_TYPE_GUEST, login::GuestAccountId()));
 
   bool allow_guest;
   cros_settings_->GetBoolean(kAccountsPrefAllowGuest, &allow_guest);
   if (!allow_guest) {
     // Disallowed. The UI should normally not show the guest session button.
     LOG(ERROR) << "Guest login attempt when guest mode is disallowed.";
     PerformLoginFinishedActions(true /* start public session timer */);
     display_email_.clear();
     return;
   }
@@ skipping 82 matching lines @@
   host_->StartAppLaunch(app_id, diagnostic_mode, auto_start);
 }
 
 void ExistingUserController::ConfigurePublicSessionAutoLogin() {
   std::string auto_login_account_id;
   cros_settings_->GetString(kAccountsPrefDeviceLocalAccountAutoLoginId,
                             &auto_login_account_id);
   const std::vector<policy::DeviceLocalAccount> device_local_accounts =
       policy::GetDeviceLocalAccounts(cros_settings_);
 
-  public_session_auto_login_username_.clear();
+  public_session_auto_login_account_id_ = EmptyAccountId();
   for (std::vector<policy::DeviceLocalAccount>::const_iterator
            it = device_local_accounts.begin();
        it != device_local_accounts.end(); ++it) {
     if (it->account_id == auto_login_account_id) {
-      public_session_auto_login_username_ = it->user_id;
+      public_session_auto_login_account_id_ =
+          AccountId::FromUserEmail(it->user_id);
       break;
     }
   }
 
   const user_manager::User* user = user_manager::UserManager::Get()->FindUser(
-      AccountId::FromUserEmail(public_session_auto_login_username_));
+      public_session_auto_login_account_id_);
   if (!user || user->GetType() != user_manager::USER_TYPE_PUBLIC_ACCOUNT)
-    public_session_auto_login_username_.clear();
+    public_session_auto_login_account_id_ = EmptyAccountId();
 
   if (!cros_settings_->GetInteger(
           kAccountsPrefDeviceLocalAccountAutoLoginDelay,
           &public_session_auto_login_delay_)) {
     public_session_auto_login_delay_ = 0;
   }
 
-  if (!public_session_auto_login_username_.empty())
+  if (public_session_auto_login_account_id_.is_valid())
     StartPublicSessionAutoLoginTimer();
   else
     StopPublicSessionAutoLoginTimer();
 }
 
 void ExistingUserController::ResetPublicSessionAutoLoginTimer() {
   // Only restart the auto-login timer if it's already running.
   if (auto_login_timer_ && auto_login_timer_->IsRunning()) {
     StopPublicSessionAutoLoginTimer();
     StartPublicSessionAutoLoginTimer();
   }
 }
 
 void ExistingUserController::OnPublicSessionAutoLoginTimerFire() {
-  CHECK(signin_screen_ready_ && !public_session_auto_login_username_.empty());
+  CHECK(signin_screen_ready_ &&
+        public_session_auto_login_account_id_.is_valid());
   Login(UserContext(user_manager::USER_TYPE_PUBLIC_ACCOUNT,
-                    public_session_auto_login_username_),
+                    public_session_auto_login_account_id_),
         SigninSpecifics());
 }
 
 void ExistingUserController::StopPublicSessionAutoLoginTimer() {
   if (auto_login_timer_)
     auto_login_timer_->Stop();
 }
 
 void ExistingUserController::StartPublicSessionAutoLoginTimer() {
-  if (!signin_screen_ready_ ||
-      is_login_in_progress_ ||
-      public_session_auto_login_username_.empty()) {
+  if (!signin_screen_ready_ || is_login_in_progress_ ||
+      !public_session_auto_login_account_id_.is_valid()) {
     return;
   }
 
   // Start the auto-login timer.
   if (!auto_login_timer_)
     auto_login_timer_.reset(new base::OneShotTimer);
 
   auto_login_timer_->Start(
       FROM_HERE,
       base::TimeDelta::FromMilliseconds(
@@ skipping 294 matching lines @@
   if (!success) {
     LOG(ERROR) << "OAuth2 token fetch failed.";
     OnAuthFailure(AuthFailure(AuthFailure::FAILED_TO_INITIALIZE_TOKEN));
     return;
   }
   UserSessionManager::GetInstance()->OnOAuth2TokensFetched(user_context);
   PerformLogin(user_context, LoginPerformer::AUTH_MODE_EXTENSION);
 }
 
 }  // namespace chromeos