[multi-profiles] Allow bringing up sign in UI even if all users are restricted per their policies

chrome/browser/chromeos/login/users/user_manager.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_
 
 #include <string>
 
 #include "chrome/browser/chromeos/base/locale_util.h"
@@ skipping 115 matching lines @@
 
   virtual MultiProfileUserController* GetMultiProfileUserController() = 0;
   virtual UserImageManager* GetUserImageManager(const std::string& user_id) = 0;
   virtual SupervisedUserManager* GetSupervisedUserManager() = 0;
 
   // Returns a list of users who have logged into this device previously. This
   // is sorted by last login date with the most recent user at the beginning.
   virtual const UserList& GetUsers() const = 0;
 
   // Returns list of users admitted for logging in into multi-profile session.
+  // Users that have a policy that prevents them from being added to the
+  // multi-profile session will still be part of this list as long as they
+  // are regular users (i.e. not a public session/supervised etc.).
+  // Returns an empty list in case when primary user is not a regular one or
+  // has a policy that prohibids it to be part of multi-profile session.
   virtual UserList GetUsersAdmittedForMultiProfile() const = 0;
 
   // Returns a list of users who are currently logged in.
   virtual const UserList& GetLoggedInUsers() const = 0;
 
   // Returns a list of users who are currently logged in in the LRU order -
   // so the active user is the first one in the list. If there is no user logged
   // in, the current user will be returned.
   virtual const UserList& GetLRULoggedInUsers() = 0;
 
@@ skipping 257 matching lines @@
   ScopedTestUserManager();
   ~ScopedTestUserManager();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedTestUserManager);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_USERS_USER_MANAGER_H_