Remove unused code

printing/printing_context_system_dialog_win.h

Index: printing/printing_context_system_dialog_win.h
diff --git a/printing/printing_context_system_dialog_win.h b/printing/printing_context_system_dialog_win.h
index 216cdd3e6fa3c43be3798601562aee9ad85a7e52..5e11aa5dbc8853260b83d6f44027520709178f88 100644
--- a/printing/printing_context_system_dialog_win.h
+++ b/printing/printing_context_system_dialog_win.h
@@ -27,7 +27,6 @@ class PRINTING_EXPORT PrintingContextSytemDialogWin
       bool has_selection,
       bool is_scripted,
       const PrintSettingsCallback& callback) override;
-  virtual void Cancel() override;
 
  private:
   friend class MockPrintingContextWin;
@@ -46,9 +45,6 @@ class PRINTING_EXPORT PrintingContextSytemDialogWin
   Result ParseDialogResultEx(const PRINTDLGEX& dialog_options);
   Result ParseDialogResult(const PRINTDLG& dialog_options);
 
-  // The dialog box for the time it is shown.
-  volatile HWND dialog_box_;
-
   DISALLOW_COPY_AND_ASSIGN(PrintingContextSytemDialogWin);
 };