Remove DialogDelegate::OnClosed() which is redundant with

chrome/browser/ui/views/first_run_dialog.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_VIEWS_FIRST_RUN_DIALOG_H_
 #define CHROME_BROWSER_UI_VIEWS_FIRST_RUN_DIALOG_H_
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "ui/views/controls/link_listener.h"
@@ skipping 15 matching lines @@
 
  private:
   explicit FirstRunDialog(Profile* profile);
   ~FirstRunDialog() override;
 
   // This terminates the nested message-loop.
   void Done();
 
   // views::DialogDelegate:
   views::View* CreateExtraView() override;
-  void OnClosed() override;
   bool Accept() override;
   int GetDialogButtons() const override;
 
+  // views::WidgetDelegate:
+  void WindowClosing() override;
+
   // views::LinkListener:
   void LinkClicked(views::Link* source, int event_flags) override;
 
   Profile* profile_;
   views::Checkbox* make_default_;
   views::Checkbox* report_crashes_;
   base::Closure quit_runloop_;
 
   DISALLOW_COPY_AND_ASSIGN(FirstRunDialog);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FIRST_RUN_DIALOG_H_