[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

Index: chrome/browser/chromeos/login/users/user_manager.h
diff --git a/chrome/browser/chromeos/login/users/user_manager.h b/chrome/browser/chromeos/login/users/user_manager.h
index 98ab8331395393b467df01dfa77a3f5b90bb59a7..cddca03de2f4bc4e50fe77643607591d00bcf753 100644
--- a/chrome/browser/chromeos/login/users/user_manager.h
+++ b/chrome/browser/chromeos/login/users/user_manager.h
@@ -133,6 +133,11 @@ class UserManager {
   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.