Fix crash on ARC Kiosk cancellation

Finalizing LoginDisplayHost before AttemptUserExit caused
double deletion of LoginDisplayHost and a crash that
leaded to not remembering error KioskAppLaunchError in a pref.

Bug: 879652
Test: Manual
Change-Id: I291872af300d99940cb9199cbdf62b01918ffbdc
Reviewed-on: https://chromium-review.googlesource.com/1234476Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Sergey Poromov <poromov@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592505}

chrome/browser/chromeos/login/arc_kiosk_controller.cc

@@ -58,14 +58,13 @@ void ArcKioskController::CleanUp() {
   // Delegate is registered only when |profile_| is set.
   if (profile_)
     ArcKioskAppService::Get(profile_)->SetDelegate(nullptr);
-
-  host_->Finalize(base::OnceClosure());
 }
 
 void ArcKioskController::CloseSplashScreen() {
   if (!launched_)
     return;
   CleanUp();
+  host_->Finalize(base::OnceClosure());
   session_manager::SessionManager::Get()->SessionStarted();
 }