Revert of More System Dialog printing code disabled on Windows.

chrome/browser/ui/webui/print_preview/print_preview_ui.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 CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_PRINT_PREVIEW_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_PRINT_PREVIEW_UI_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
@@ skipping 66 matching lines @@
   static void GetCurrentPrintPreviewStatus(int32 preview_ui_id,
                                            int request_id,
                                            bool* cancel);
 
   // Returns an id to uniquely identify this PrintPreviewUI.
   int32 GetIDForPrintPreviewUI() const;
 
   // Notifies the Web UI of a print preview request with |request_id|.
   void OnPrintPreviewRequest(int request_id);
 
-#if !defined(OS_WIN)
   // Notifies the Web UI to show the system dialog.
   void OnShowSystemDialog();
-#endif  // !OS_WIN
 
   // Notifies the Web UI about the page count of the request preview.
   void OnDidGetPreviewPageCount(
       const PrintHostMsg_DidGetPreviewPageCount_Params& params);
 
   // Notifies the Web UI of the default page layout according to the currently
   // selected printer and page size.
   void OnDidGetDefaultPageLayout(const printing::PageSizeMargins& page_layout,
                                  const gfx::Rect& printable_area,
                                  bool has_custom_page_size_style);
@@ skipping 103 matching lines @@
   // title.
   base::string16 initiator_title_;
 
   // Keeps track of whether OnClosePrintPreviewDialog() has been called or not.
   bool dialog_closed_;
 
   DISALLOW_COPY_AND_ASSIGN(PrintPreviewUI);
 };
 
 #endif  // CHROME_BROWSER_UI_WEBUI_PRINT_PREVIEW_PRINT_PREVIEW_UI_H_