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

chrome/browser/profiles/profile_manager.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.
 
 // This class keeps track of the currently-active profiles in the runtime.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_
 
 #include <list>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/non_thread_safe.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_shortcut_manager.h"
 #include "chrome/browser/ui/browser_list_observer.h"
+#include "components/user_manager/user_id.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class NewProfileLauncher;
 class ProfileInfoCache;
 
 class ProfileManager : public base::NonThreadSafe,
                        public content::NotificationObserver,
                        public Profile::Delegate {
  public:
@@ skipping 50 matching lines @@
   // Returns total number of profiles available on this machine.
   size_t GetNumberOfProfiles();
 
   // Explicit asynchronous creation of a profile located at |profile_path|.
   // If the profile has already been created then callback is called
   // immediately. Should be called on the UI thread.
   void CreateProfileAsync(const base::FilePath& profile_path,
                           const CreateCallback& callback,
                           const base::string16& name,
                           const base::string16& icon_url,
-                          const std::string& supervised_user_id);
+                          const user_manager::UserID& supervised_user_id);
 
   // Returns true if the profile pointer is known to point to an existing
   // profile.
   bool IsValidProfile(Profile* profile);
 
   // Returns the directory where the first created profile is stored,
   // relative to the user data directory currently in use.
   base::FilePath GetInitialProfileDir();
 
   // Get the Profile last used (the Profile to which owns the most recently
@@ skipping 31 matching lines @@
   // creation. (Because directories can be removed, however, it may be the case
   // that at some point the list of numbered profiles is not continuous.)
   // |callback| may be invoked multiple times (for CREATE_STATUS_INITIALIZED
   // and CREATE_STATUS_CREATED) so binding parameters with bind::Passed() is
   // prohibited. Returns the file path to the profile that will be created
   // asynchronously.
   static base::FilePath CreateMultiProfileAsync(
       const base::string16& name,
       const base::string16& icon_url,
       const CreateCallback& callback,
-      const std::string& supervised_user_id);
+      const user_manager::UserID& supervised_user_id);
 
   // Returns the full path to be used for guest profiles.
   static base::FilePath GetGuestProfilePath();
 
   // Returns the full path to be used for system profiles.
   static base::FilePath GetSystemProfilePath();
 
   // Get the path of the next profile directory and increment the internal
   // count.
   // Lack of side effects:
@@ skipping 217 matching lines @@
 class ProfileManagerWithoutInit : public ProfileManager {
  public:
   explicit ProfileManagerWithoutInit(const base::FilePath& user_data_dir);
 
  protected:
   void DoFinalInitForServices(Profile*, bool) override {}
   void DoFinalInitLogging(Profile*) override {}
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_MANAGER_H_