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

chrome/browser/chromeos/login/users/chrome_user_manager_impl.cc

 // Copyright 2014 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/users/chrome_user_manager_impl.h"
 
 #include <stddef.h>
 #include <cstddef>
 #include <set>
 #include <utility>
@@ skipping 1233 matching lines @@
 }
 
 bool ChromeUserManagerImpl::IsFirstExecAfterBoot() const {
   return base::CommandLine::ForCurrentProcess()->HasSwitch(
       chromeos::switches::kFirstExecAfterBoot);
 }
 
 void ChromeUserManagerImpl::AsyncRemoveCryptohome(
     const AccountId& account_id) const {
   cryptohome::AsyncMethodCaller::GetInstance()->AsyncRemove(
-      account_id.GetUserEmail(), base::Bind(&OnRemoveUserComplete, account_id));
+      cryptohome::Identification(account_id),
+      base::Bind(&OnRemoveUserComplete, account_id));
 }
 
 bool ChromeUserManagerImpl::IsGuestAccountId(
     const AccountId& account_id) const {
   return account_id == login::GuestAccountId();
 }
 
 bool ChromeUserManagerImpl::IsStubAccountId(const AccountId& account_id) const {
   return account_id == login::StubAccountId();
 }
@@ skipping 29 matching lines @@
       base::Bind(ResolveLocale, locale, base::Unretained(out_resolved_locale)),
       on_resolved_callback);
 }
 
 bool ChromeUserManagerImpl::IsValidDefaultUserImageId(int image_index) const {
   return image_index >= 0 &&
          image_index < chromeos::default_user_image::kDefaultImagesCount;
 }
 
 }  // namespace chromeos