Use JS Date().toLocaleDateString() to format date in header.

printing/print_settings.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 PRINTING_PRINT_SETTINGS_H_
 #define PRINTING_PRINT_SETTINGS_H_
 
 #include <string>
 
 #include "base/strings/string16.h"
@@ skipping 91 matching lines @@
 
   // Cookie generator. It is used to initialize PrintedDocument with its
   // associated PrintSettings, to be sure that each generated PrintedPage is
   // correctly associated with its corresponding PrintedDocument.
   static int NewCookie();
 
   // Updates the orientation and flip the page if needed.
   void SetOrientation(bool landscape);
 
   // Strings to be printed as headers and footers if requested by the user.
-  base::string16 date;
   base::string16 title;
   base::string16 url;
 
   // True if the user wants headers and footers to be displayed.
   bool display_header_footer;
 
   // True if the user wants to print CSS backgrounds.
   bool should_print_backgrounds;
 
  private:
@@ skipping 18 matching lines @@
   // True if this printer supports AlphaBlend.
   bool supports_alpha_blend_;
 
   // If margin type is custom, this is what was requested.
   PageMargins requested_custom_margins_in_points_;
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_PRINT_SETTINGS_H_