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

chrome/browser/chromeos/policy/device_local_account_policy_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_LOCAL_ACCOUNT_POLICY_SERVICE_H_
 #define CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_LOCAL_ACCOUNT_POLICY_SERVICE_H_
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "chrome/browser/chromeos/extensions/device_local_account_external_policy_loader.h"
 #include "chrome/browser/chromeos/policy/device_local_account_extension_tracker.h"
 #include "chrome/browser/chromeos/policy/device_local_account_external_data_manager.h"
 #include "chrome/browser/chromeos/settings/cros_settings.h"
 #include "components/policy/core/common/cloud/cloud_policy_core.h"
 #include "components/policy/core/common/cloud/cloud_policy_store.h"
 #include "components/policy/core/common/cloud/component_cloud_policy_service.h"
 #include "components/policy/core/common/schema_registry.h"
+#include "components/user_manager/user_id.h"
 
 namespace base {
 class SequencedTaskRunner;
 }
 
 namespace chromeos {
 class DeviceSettingsService;
 class SessionManagerClient;
 }
 
@@ skipping 30 matching lines @@
       const scoped_refptr<base::SequencedTaskRunner>& task_runner,
       AffiliatedInvalidationServiceProvider* invalidation_service_provider);
   ~DeviceLocalAccountPolicyBroker() override;
 
   // Initialize the broker, loading its |store_|.
   void Initialize();
 
   // For the difference between |account_id| and |user_id|, see the
   // documentation of DeviceLocalAccount.
   const std::string& account_id() const { return account_id_; }
-  const std::string& user_id() const { return user_id_; }
+  const user_manager::UserID& user_id() const { return user_id_; }
 
   scoped_refptr<chromeos::DeviceLocalAccountExternalPolicyLoader>
       extension_loader() const { return extension_loader_; }
 
   CloudPolicyCore* core() { return &core_; }
   const CloudPolicyCore* core() const { return &core_; }
 
   scoped_refptr<DeviceLocalAccountExternalDataManager> external_data_manager() {
     return external_data_manager_;
   }
@@ skipping 27 matching lines @@
   // ComponentCloudPolicyService::Delegate:
   void OnComponentCloudPolicyUpdated() override;
 
  private:
   void CreateComponentCloudPolicyService(
       const scoped_refptr<net::URLRequestContextGetter>& request_context,
       CloudPolicyClient* client);
 
   AffiliatedInvalidationServiceProvider* const invalidation_service_provider_;
   const std::string account_id_;
-  const std::string user_id_;
+  const user_manager::UserID user_id_;
   const base::FilePath component_policy_cache_path_;
   SchemaRegistry schema_registry_;
   const scoped_ptr<DeviceLocalAccountPolicyStore> store_;
   DeviceLocalAccountExtensionTracker extension_tracker_;
   scoped_refptr<DeviceLocalAccountExternalDataManager> external_data_manager_;
   scoped_refptr<chromeos::DeviceLocalAccountExternalPolicyLoader>
       extension_loader_;
   CloudPolicyCore core_;
   scoped_ptr<ComponentCloudPolicyService> component_policy_service_;
   base::Closure policy_update_callback_;
   scoped_ptr<AffiliatedCloudPolicyInvalidator> invalidator_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceLocalAccountPolicyBroker);
 };
 
 // Manages user policy blobs for device-local accounts present on the device.
 // The actual policy blobs are brokered by session_manager (to prevent file
 // manipulation), and we're making signature checks on the policy blobs to
 // ensure they're issued by the device owner.
 class DeviceLocalAccountPolicyService {
  public:
   // Interface for interested parties to observe policy changes.
   class Observer {
    public:
     virtual ~Observer() {}
 
     // Policy for the given |user_id| has changed.
-    virtual void OnPolicyUpdated(const std::string& user_id) = 0;
+    virtual void OnPolicyUpdated(const user_manager::UserID& user_id) = 0;
 
     // The list of accounts has been updated.
     virtual void OnDeviceLocalAccountsChanged() = 0;
   };
 
   DeviceLocalAccountPolicyService(
       chromeos::SessionManagerClient* session_manager_client,
       chromeos::DeviceSettingsService* device_settings_service,
       chromeos::CrosSettings* cros_settings,
       AffiliatedInvalidationServiceProvider* invalidation_service_provider,
       scoped_refptr<base::SequencedTaskRunner> store_background_task_runner,
       scoped_refptr<base::SequencedTaskRunner> extension_cache_task_runner,
       scoped_refptr<base::SequencedTaskRunner>
           external_data_service_backend_task_runner,
       scoped_refptr<base::SequencedTaskRunner> io_task_runner,
       scoped_refptr<net::URLRequestContextGetter> request_context);
   virtual ~DeviceLocalAccountPolicyService();
 
   // Shuts down the service and prevents further policy fetches from the cloud.
   void Shutdown();
 
   // Initializes the cloud policy service connection.
   void Connect(DeviceManagementService* device_management_service);
 
   // Get the policy broker for a given |user_id|. Returns NULL if that |user_id|
   // does not belong to an existing device-local account.
-  DeviceLocalAccountPolicyBroker* GetBrokerForUser(const std::string& user_id);
+  DeviceLocalAccountPolicyBroker* GetBrokerForUser(const user_manager::UserID& user_id);
 
   // Indicates whether policy has been successfully fetched for the given
   // |user_id|.
-  bool IsPolicyAvailableForUser(const std::string& user_id);
+  bool IsPolicyAvailableForUser(const user_manager::UserID& user_id);
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
  private:
-  typedef std::map<std::string, DeviceLocalAccountPolicyBroker*>
+  typedef std::map<user_manager::UserID, DeviceLocalAccountPolicyBroker*>
       PolicyBrokerMap;
 
   // Returns |true| if the directory in which force-installed extensions are
   // cached for |account_id| is busy, either because a broker that was using
   // this directory has not shut down completely yet or because the directory is
   // being deleted.
   bool IsExtensionCacheDirectoryBusy(const std::string& account_id);
 
   // Starts any extension caches that are not running yet but can be started now
   // because their cache directories are no longer busy.
@@ skipping 20 matching lines @@
   // Calls |UpdateAccountList| if there are no previous calls pending.
   void UpdateAccountListIfNonePending();
 
   // Deletes brokers in |map| and clears it.
   void DeleteBrokers(PolicyBrokerMap* map);
 
   // Find the broker for a given |store|. Returns NULL if |store| is unknown.
   DeviceLocalAccountPolicyBroker* GetBrokerForStore(CloudPolicyStore* store);
 
   // Notifies the |observers_| that the policy for |user_id| has changed.
-  void NotifyPolicyUpdated(const std::string& user_id);
+  void NotifyPolicyUpdated(const user_manager::UserID& user_id);
 
   ObserverList<Observer, true> observers_;
 
   chromeos::SessionManagerClient* session_manager_client_;
   chromeos::DeviceSettingsService* device_settings_service_;
   chromeos::CrosSettings* cros_settings_;
   AffiliatedInvalidationServiceProvider* invalidation_service_provider_;
 
   DeviceManagementService* device_management_service_;
 
@@ skipping 33 matching lines @@
   base::FilePath component_policy_cache_root_;
 
   base::WeakPtrFactory<DeviceLocalAccountPolicyService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceLocalAccountPolicyService);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_DEVICE_LOCAL_ACCOUNT_POLICY_SERVICE_H_