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

chrome/browser/chromeos/login/supervised/supervised_user_authenticator.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/supervised/supervised_user_authenticator.h"
 
 #include "base/bind.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "chrome/browser/chromeos/boot_times_recorder.h"
@@ skipping 50 matching lines @@
            scoped_refptr<SupervisedUserAuthenticator> resolver,
            int flags,
            const std::string& system_salt) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   chromeos::BootTimesRecorder::Get()->AddLoginTimeMarker(
       "CryptohomeMount-LMU-Start", false);
 
   Key key(attempt->password);
   key.Transform(Key::KEY_TYPE_SALTED_SHA256_TOP_HALF, system_salt);
   cryptohome::AsyncMethodCaller::GetInstance()->AsyncMount(
-      attempt->username,
+      attempt->user_id,
       key.GetSecret(),
       flags,
       base::Bind(&TriggerResolveWithLoginTimeMarker,
                  "CryptohomeMount-LMU-End",
                  attempt,
                  resolver));
 
   cryptohome::AsyncMethodCaller::GetInstance()->AsyncGetSanitizedUsername(
-      attempt->username,
+      attempt->user_id,
       base::Bind(&TriggerResolveResult, attempt, resolver));
 }
 
 // Calls cryptohome's addKey method.
 void AddKey(SupervisedUserAuthenticator::AuthAttempt* attempt,
             scoped_refptr<SupervisedUserAuthenticator> resolver,
             const std::string& plain_text_master_key,
             const std::string& system_salt) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   chromeos::BootTimesRecorder::Get()->AddLoginTimeMarker(
       "CryptohomeAddKey-LMU-Start", false);
 
   Key user_key(attempt->password);
   user_key.Transform(Key::KEY_TYPE_SALTED_SHA256_TOP_HALF, system_salt);
   Key master_key(plain_text_master_key);
   master_key.Transform(Key::KEY_TYPE_SALTED_SHA256_TOP_HALF, system_salt);
   cryptohome::AsyncMethodCaller::GetInstance()->AsyncAddKey(
-      attempt->username,
+      attempt->user_id,
       user_key.GetSecret(),
       master_key.GetSecret(),
       base::Bind(&TriggerResolveWithLoginTimeMarker,
                  "CryptohomeAddKey-LMU-End",
                  attempt,
                  resolver));
 }
 
 }  // namespace
 
 SupervisedUserAuthenticator::SupervisedUserAuthenticator(
     AuthStatusConsumer* consumer)
     : consumer_(consumer) {}
 
 void SupervisedUserAuthenticator::AuthenticateToMount(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& password) {
-  std::string canonicalized = gaia::CanonicalizeEmail(username);
-
   current_state_.reset(new SupervisedUserAuthenticator::AuthAttempt(
-      canonicalized, password, false));
+      user_id, password, false));
 
   SystemSaltGetter::Get()->GetSystemSalt(
       base::Bind(&Mount,
                  current_state_.get(),
                  scoped_refptr<SupervisedUserAuthenticator>(this),
                  cryptohome::MOUNT_FLAGS_NONE));
 }
 
 void SupervisedUserAuthenticator::AuthenticateToCreate(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& password) {
-  std::string canonicalized = gaia::CanonicalizeEmail(username);
-
   current_state_.reset(new SupervisedUserAuthenticator::AuthAttempt(
-      canonicalized, password, false));
+      user_id, password, false));
 
   SystemSaltGetter::Get()->GetSystemSalt(
       base::Bind(&Mount,
                  current_state_.get(),
                  scoped_refptr<SupervisedUserAuthenticator>(this),
                  cryptohome::CREATE_IF_MISSING));
 }
 
 void SupervisedUserAuthenticator::AddMasterKey(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& password,
     const std::string& master_key) {
-  std::string canonicalized = gaia::CanonicalizeEmail(username);
-
   current_state_.reset(new SupervisedUserAuthenticator::AuthAttempt(
-      canonicalized, password, true));
+      user_id, password, true));
 
   SystemSaltGetter::Get()->GetSystemSalt(
       base::Bind(&AddKey,
                  current_state_.get(),
                  scoped_refptr<SupervisedUserAuthenticator>(this),
                  master_key));
 }
 
 void SupervisedUserAuthenticator::OnAuthenticationSuccess(
     const std::string& mount_hash,
@@ skipping 120 matching lines @@
   return FAILED_MOUNT;
 }
 
 SupervisedUserAuthenticator::AuthState
     SupervisedUserAuthenticator::ResolveCryptohomeSuccessState() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return SUCCESS;
 }
 
 SupervisedUserAuthenticator::AuthAttempt::AuthAttempt(
-    const std::string& username,
+    const user_manager::UserID& user_id,
     const std::string& password,
     bool add_key_attempt)
-    : username(username),
+    : user_id(user_id),
       password(password),
       add_key(add_key_attempt),
       cryptohome_complete_(false),
       cryptohome_outcome_(false),
       hash_obtained_(false),
       cryptohome_code_(cryptohome::MOUNT_ERROR_NONE) {}
 
 SupervisedUserAuthenticator::AuthAttempt::~AuthAttempt() {}
 
 void SupervisedUserAuthenticator::AuthAttempt::RecordCryptohomeStatus(
@@ skipping 32 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return hash_obtained_;
 }
 
 std::string SupervisedUserAuthenticator::AuthAttempt::hash() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   return hash_;
 }
 
 }  // namespace chromeos