Update {virtual,override} to follow C++11 style in printing.

printing/printing_context_system_dialog_win.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 PRINTING_PRINTING_CONTEXT_SYSTEM_DIALOG_WIN_H_
 #define PRINTING_PRINTING_CONTEXT_SYSTEM_DIALOG_WIN_H_
 
 #include <ocidl.h>
 #include <commdlg.h>
 
 #include <string>
 
 #include "printing/printing_context_win.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace printing {
 
 class PRINTING_EXPORT PrintingContextSytemDialogWin
     : public PrintingContextWin {
  public:
   explicit PrintingContextSytemDialogWin(Delegate* delegate);
-  virtual ~PrintingContextSytemDialogWin();
+  ~PrintingContextSytemDialogWin() override;
 
   // PrintingContext implementation.
-  virtual void AskUserForSettings(
+  void AskUserForSettings(
       int max_pages,
       bool has_selection,
       bool is_scripted,
       const PrintSettingsCallback& callback) override;
 
  private:
   friend class MockPrintingContextWin;
 
   virtual HRESULT ShowPrintDialog(PRINTDLGEX* options);
 
   // Reads the settings from the selected device context. Updates settings_ and
   // its margins.
   bool InitializeSettings(const DEVMODE& dev_mode,
                           const std::wstring& new_device_name,
                           const PRINTPAGERANGE* ranges,
                           int number_ranges,
                           bool selection_only);
 
   // Parses the result of a PRINTDLGEX result.
   Result ParseDialogResultEx(const PRINTDLGEX& dialog_options);
   Result ParseDialogResult(const PRINTDLG& dialog_options);
 
   DISALLOW_COPY_AND_ASSIGN(PrintingContextSytemDialogWin);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINTING_CONTEXT_SYSTEM_DIALOG_WIN_H_