Enable "Hide Extension" option when "Save Link As" on the Mac

chrome/browser/download/download_target_info.h

 // Copyright 2013 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_DOWNLOAD_DOWNLOAD_TARGET_INFO_H_
 #define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_INFO_H_
 
 #include "base/files/file_path.h"
 #include "content/public/browser/download_danger_type.h"
 #include "content/public/browser/download_item.h"
@@ skipping 35 matching lines @@
   // MIME type based on the file type of the download. This may be different
   // from DownloadItem::GetMimeType() since the latter is based on the server
   // response, and this one is based on the filename.
   std::string mime_type;
 
   // Whether the |target_path| would be handled safely by the browser if it were
   // to be opened with a file:// URL. This can be used later to decide how file
   // opens should be handled. The file is considered to be handled safely if the
   // filetype is supported by the renderer or a sandboxed plugin.
   bool is_filetype_handled_safely;
+
+  // Whether |target_path| should be configured to hide its file extesnion in
+  // the Finder (MacOSX).
+  bool hide_file_extension;
 };
 
 #endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_TARGET_INFO_H_