Introduce profile for lock screen apps

chrome/browser/supervised_user/child_accounts/child_account_service.cc

Index: chrome/browser/supervised_user/child_accounts/child_account_service.cc
diff --git a/chrome/browser/supervised_user/child_accounts/child_account_service.cc b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
index 8fefedcb91dc049739d075557fbd0dccb0c9b595..842021e07068f80fb0a931a234c11ba2066659dc 100644
--- a/chrome/browser/supervised_user/child_accounts/child_account_service.cc
+++ b/chrome/browser/supervised_user/child_accounts/child_account_service.cc
@@ -363,10 +363,13 @@ void ChildAccountService::PropagateChildStatusToUser(bool is_child) {
 #if defined(OS_CHROMEOS)
   user_manager::User* user =
       chromeos::ProfileHelper::Get()->GetUserByProfile(profile_);
-  if (user)
+  if (user) {
     user_manager::UserManager::Get()->ChangeUserChildStatus(user, is_child);
-  else if (!chromeos::ProfileHelper::Get()->IsSigninProfile(profile_))
+  } else if (!chromeos::ProfileHelper::Get()->IsSigninProfile(profile_) &&
+             !chromeos::ProfileHelper::Get()->IsLockScreenAppProfile(
+                 profile_)) {
     LOG(DFATAL) << "User instance not found while setting child account flag.";
+  }
 #endif
 }