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

components/app_modal/views/javascript_app_modal_dialog_views.h

 // Copyright (c) 2012 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.
 
 #ifndef COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_
 #define COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/app_modal/native_app_modal_dialog.h"
@@ skipping 28 matching lines @@
   base::string16 GetWindowTitle() const override;
   void DeleteDelegate() override;
   bool Cancel() override;
   bool Accept() override;
   base::string16 GetDialogButtonLabel(ui::DialogButton button) const override;
 
   // Overridden from views::WidgetDelegate:
   ui::ModalType GetModalType() const override;
   views::View* GetContentsView() override;
   views::View* GetInitiallyFocusedView() override;
-  void WindowClosing() override;
+  void OnClosed() override;
   views::Widget* GetWidget() override;
   const views::Widget* GetWidget() const override;
 
  private:
   // A pointer to the AppModalDialog that owns us.
   scoped_ptr<JavaScriptAppModalDialog> parent_;
 
   // The message box view whose commands we handle.
   views::MessageBoxView* message_box_view_;
 
   DISALLOW_COPY_AND_ASSIGN(JavaScriptAppModalDialogViews);
 };
 
 }  // namespace app_modal
 
 #endif  // COMPONENTS_APP_MODAL_VIEWS_JAVASCRIPT_APP_MODAL_DIALOG_VIEWS_H_