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

chromeos/dbus/session_manager_client.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 CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_
 #define CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/observer_list.h"
 #include "chromeos/chromeos_export.h"
 #include "chromeos/dbus/dbus_client.h"
 #include "chromeos/dbus/dbus_client_implementation_type.h"
 
+namespace user_manager {
+class UserID;
+}
+
 namespace chromeos {
 
 // SessionManagerClient is used to communicate with the session manager.
 class CHROMEOS_EXPORT SessionManagerClient : public DBusClient {
  public:
   // Interface for observing changes from the session manager.
   class Observer {
    public:
     virtual ~Observer() {}
 
@@ skipping 42 matching lines @@
   // call.
   virtual bool IsScreenLocked() const = 0;
 
   // Kicks off an attempt to emit the "login-prompt-visible" upstart signal.
   virtual void EmitLoginPromptVisible() = 0;
 
   // Restarts a job referenced by |pid| with the provided command line.
   virtual void RestartJob(int pid, const std::string& command_line) = 0;
 
   // Starts the session for the user.
-  virtual void StartSession(const std::string& user_email) = 0;
+  virtual void StartSession(const user_manager::UserID& user_id) = 0;
 
   // Stops the current session.
   virtual void StopSession() = 0;
 
   // Starts the factory reset.
   virtual void StartDeviceWipe() = 0;
 
   // Locks the screen.
   virtual void RequestLockScreen() = 0;
 
   // Notifies that the lock screen is shown.
   virtual void NotifyLockScreenShown() = 0;
 
   // Notifies that the lock screen is dismissed.
   virtual void NotifyLockScreenDismissed() = 0;
 
   // Notifies that supervised user creation have started.
   virtual void NotifySupervisedUserCreationStarted() = 0;
 
   // Notifies that supervised user creation have finished.
   virtual void NotifySupervisedUserCreationFinished() = 0;
 
   // Map that is used to describe the set of active user sessions where |key|
   // is user_id and |value| is user_id_hash.
-  typedef std::map<std::string, std::string> ActiveSessionsMap;
+  typedef std::map<user_manager::UserID, std::string> ActiveSessionsMap;
 
   // The ActiveSessionsCallback is used for the RetrieveActiveSessions()
   // method. It receives |sessions| argument where the keys are user_ids for
   // all users that are currently active and |success| argument which indicates
   // whether or not the request succeded.
   typedef base::Callback<void(const ActiveSessionsMap& sessions,
                               bool success)> ActiveSessionsCallback;
 
   // Enumerates active user sessions. Usually Chrome naturally keeps track of
   // active users when they are added into current session. When Chrome is
   // restarted after crash by session_manager it only receives user_id and
   // user_id_hash for one user. This method is used to retrieve list of all
   // active users.
   virtual void RetrieveActiveSessions(
       const ActiveSessionsCallback& callback) = 0;
 
   // Used for RetrieveDevicePolicy, RetrievePolicyForUser and
   // RetrieveDeviceLocalAccountPolicy. Takes a serialized protocol buffer as
   // string.  Upon success, we will pass a protobuf to the callback.  On
   // failure, we will pass "".
   typedef base::Callback<void(const std::string&)> RetrievePolicyCallback;
 
   // Fetches the device policy blob stored by the session manager.  Upon
   // completion of the retrieve attempt, we will call the provided callback.
   virtual void RetrieveDevicePolicy(const RetrievePolicyCallback& callback) = 0;
 
   // Fetches the user policy blob stored by the session manager for the given
-  // |username|. Upon completion of the retrieve attempt, we will call the
+  // |user_id|. Upon completion of the retrieve attempt, we will call the
   // provided callback.
   virtual void RetrievePolicyForUser(
-      const std::string& username,
+      const user_manager::UserID& user_id,
       const RetrievePolicyCallback& callback) = 0;
 
   // Same as RetrievePolicyForUser() but blocks until a reply is received, and
   // returns the policy synchronously. Returns an empty string if the method
   // call fails.
   // This may only be called in situations where blocking the UI thread is
   // considered acceptable (e.g. restarting the browser after a crash or after
   // a flag change).
   virtual std::string BlockingRetrievePolicyForUser(
-      const std::string& username) = 0;
+      const user_manager::UserID& user_id) = 0;
 
   // Fetches the policy blob associated with the specified device-local account
   // from session manager.  |callback| is invoked up on completion.
   virtual void RetrieveDeviceLocalAccountPolicy(
       const std::string& account_id,
       const RetrievePolicyCallback& callback) = 0;
 
   // Used for StoreDevicePolicy, StorePolicyForUser and
   // StoreDeviceLocalAccountPolicy. Takes a boolean indicating whether the
   // operation was successful or not.
   typedef base::Callback<void(bool)> StorePolicyCallback;
 
   // Attempts to asynchronously store |policy_blob| as device policy.  Upon
   // completion of the store attempt, we will call callback.
   virtual void StoreDevicePolicy(const std::string& policy_blob,
                                  const StorePolicyCallback& callback) = 0;
 
   // Attempts to asynchronously store |policy_blob| as user policy for the given
-  // |username|. Upon completion of the store attempt, we will call callback.
-  virtual void StorePolicyForUser(const std::string& username,
+  // |user_id|. Upon completion of the store attempt, we will call callback.
+  virtual void StorePolicyForUser(const user_manager::UserID& user_id,
                                   const std::string& policy_blob,
                                   const StorePolicyCallback& callback) = 0;
 
   // Sends a request to store a policy blob for the specified device-local
   // account. The result of the operation is reported through |callback|.
   virtual void StoreDeviceLocalAccountPolicy(
       const std::string& account_id,
       const std::string& policy_blob,
       const StorePolicyCallback& callback) = 0;
 
   // Sets the flags to be applied next time by the session manager when Chrome
   // is restarted inside an already started session for a particular user.
-  virtual void SetFlagsForUser(const std::string& username,
+  virtual void SetFlagsForUser(const user_manager::UserID& user_id,
                                const std::vector<std::string>& flags) = 0;
 
   typedef base::Callback<void(const std::vector<std::string>& state_keys)>
       StateKeysCallback;
 
   // Get the currently valid server-backed state keys for the device.
   // Server-backed state keys are opaque, device-unique, time-dependent,
   // client-determined identifiers that are used for keying state in the cloud
   // for the device to retrieve after a device factory reset.
   //
@@ skipping 10 matching lines @@
   // Create() should be used instead.
   SessionManagerClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SessionManagerClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SESSION_MANAGER_CLIENT_H_