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

chromeos/tpm/tpm_token_info_getter.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 "chromeos/tpm/tpm_token_info_getter.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "chromeos/dbus/cryptohome_client.h"
 
@@ skipping 23 matching lines @@
 
 TPMTokenInfo::TPMTokenInfo()
     : tpm_is_enabled(false),
       token_slot_id(-1) {
 }
 
 TPMTokenInfo::~TPMTokenInfo() {}
 
 // static
 scoped_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForUserToken(
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     CryptohomeClient* cryptohome_client,
     const scoped_refptr<base::TaskRunner>& delayed_task_runner) {
   CHECK(!user_id.empty());
   return scoped_ptr<TPMTokenInfoGetter>(
       new TPMTokenInfoGetter(
           TYPE_USER, user_id, cryptohome_client, delayed_task_runner));
 }
 
 // static
 scoped_ptr<TPMTokenInfoGetter> TPMTokenInfoGetter::CreateForSystemToken(
     CryptohomeClient* cryptohome_client,
     const scoped_refptr<base::TaskRunner>& delayed_task_runner) {
   return scoped_ptr<TPMTokenInfoGetter>(
       new TPMTokenInfoGetter(
-          TYPE_SYSTEM, std::string(), cryptohome_client, delayed_task_runner));
+          TYPE_SYSTEM, user_manager::UserID(std::string(), std::string()), cryptohome_client, delayed_task_runner));
 }
 
 TPMTokenInfoGetter::~TPMTokenInfoGetter() {}
 
 void TPMTokenInfoGetter::Start(const TPMTokenInfoCallback& callback) {
   CHECK(state_ == STATE_INITIAL);
   CHECK(!callback.is_null());
 
   callback_ = callback;
 
   state_ = STATE_STARTED;
   Continue();
 }
 
 TPMTokenInfoGetter::TPMTokenInfoGetter(
     TPMTokenInfoGetter::Type type,
-    const std::string& user_id,
+    const user_manager::UserID& user_id,
     CryptohomeClient* cryptohome_client,
     const scoped_refptr<base::TaskRunner>& delayed_task_runner)
     : delayed_task_runner_(delayed_task_runner),
       type_(type),
       state_(TPMTokenInfoGetter::STATE_INITIAL),
       user_id_(user_id),
       tpm_request_delay_(
           base::TimeDelta::FromMilliseconds(kInitialRequestDelayMs)),
       cryptohome_client_(cryptohome_client),
       weak_factory_(this) {
@@ skipping 66 matching lines @@
   TPMTokenInfo token_info;
   token_info.tpm_is_enabled = true;
   token_info.token_name = token_name;
   token_info.user_pin = user_pin;
   token_info.token_slot_id = token_slot_id;
 
   callback_.Run(token_info);
 }
 
 }  // namespace chromeos