Revert of Remove DialogDelegate::OnClosed() which is redundant with

ash/system/chromeos/session/logout_confirmation_dialog.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_dialog.h"
 
 #include "ash/shell.h"
 #include "ash/system/chromeos/session/logout_confirmation_controller.h"
 #include "ash/system/tray/tray_constants.h"
 #include "base/location.h"
@@ skipping 66 matching lines @@
   return l10n_util::GetStringUTF16(IDS_ASH_LOGOUT_CONFIRMATION_TITLE);
 }
 
 base::string16 LogoutConfirmationDialog::GetDialogButtonLabel(
     ui::DialogButton button) const {
   if (button == ui::DIALOG_BUTTON_OK)
     return l10n_util::GetStringUTF16(IDS_ASH_LOGOUT_CONFIRMATION_BUTTON);
   return views::DialogDelegateView::GetDialogButtonLabel(button);
 }
 
-void LogoutConfirmationDialog::WindowClosing() {
+void LogoutConfirmationDialog::OnClosed() {
   update_timer_.Stop();
   controller_->OnDialogClosed();
 }
 
+void LogoutConfirmationDialog::DeleteDelegate() {
+  delete this;
+}
+
 void LogoutConfirmationDialog::UpdateLabel() {
   const base::TimeDelta time_remaining =
       logout_time_ - controller_->clock()->NowTicks();
   if (time_remaining >= base::TimeDelta::FromMilliseconds(kHalfSecondInMs)) {
     label_->SetText(l10n_util::GetStringFUTF16(
         IDS_ASH_LOGOUT_CONFIRMATION_WARNING,
         ui::TimeFormat::Detailed(ui::TimeFormat::FORMAT_DURATION,
                                  ui::TimeFormat::LENGTH_LONG,
                                  10,
                                  time_remaining)));
   } else {
     label_->SetText(l10n_util::GetStringUTF16(
         IDS_ASH_LOGOUT_CONFIRMATION_WARNING_NOW));
     update_timer_.Stop();
   }
 }
 
 }  // namespace ash