Reland: Remove DialogDelegate::OnClosed() which is redundant with

ash/system/chromeos/session/logout_confirmation_controller.cc

 // 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.
 
 #include "ash/system/chromeos/session/logout_confirmation_controller.h"
 
 #include <utility>
 
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell.h"
@@ skipping 12 matching lines @@
       dialog_(NULL),
       logout_timer_(false, false) {
   if (Shell::HasInstance())
     Shell::GetInstance()->AddShellObserver(this);
 }
 
 LogoutConfirmationController::~LogoutConfirmationController() {
   if (Shell::HasInstance())
     Shell::GetInstance()->RemoveShellObserver(this);
   if (dialog_)
-    dialog_->GetWidget()->Close();
+    dialog_->ControllerGone();
 }
 
 void LogoutConfirmationController::ConfirmLogout(
     base::TimeTicks logout_time) {
   if (!logout_time_.is_null() && logout_time >= logout_time_) {
     // If a confirmation dialog is already being shown and its countdown expires
     // no later than the |logout_time| requested now, keep the current dialog
     // open.
     return;
   }
@@ skipping 34 matching lines @@
   logout_closure_.Run();
 }
 
 void LogoutConfirmationController::OnDialogClosed() {
   logout_time_ = base::TimeTicks();
   dialog_ = NULL;
   logout_timer_.Stop();
 }
 
 }  // namespace ash