Print preview not showing if default print is invalid.

chrome/renderer/mock_printer.h

 // Copyright (c) 2011 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_RENDERER_MOCK_PRINTER_H_
 #define CHROME_RENDERER_MOCK_PRINTER_H_
 #pragma once
 
 #include <string>
 #include <vector>
@@ skipping 51 matching lines @@
     PRINTER_PRINTING,
     PRINTER_ERROR,
   };
 
   MockPrinter();
   ~MockPrinter();
 
   // Functions that changes settings of a pseudo printer.
   void ResetPrinter();
   void SetDefaultPrintSettings(const PrintMsg_Print_Params& params);
+  void UseInvalidSettings();
 
   // Functions that handles IPC events.
   void GetDefaultPrintSettings(PrintMsg_Print_Params* params);
   void ScriptedPrint(int cookie,
                      int expected_pages_count,
                      bool has_selection,
                      PrintMsg_PrintPages_Params* settings);
   void UpdateSettings(int cookie, PrintMsg_PrintPages_Params* params,
                       const std::vector<int>& page_range_array);
   void SetPrintedPagesCount(int cookie, int number_pages);
@@ skipping 53 matching lines @@
   // Used only in the preview sequence.
   bool is_first_request_;
   int preview_request_id_;
 
   // Used for displaying headers and footers.
   bool display_header_footer_;
   string16 date_;
   string16 title_;
   string16 url_;
 
+  // Used for generating invalid settings.
+  bool use_invalid_settings_;
+
   std::vector<scoped_refptr<MockPrinterPage> > pages_;
 
   DISALLOW_COPY_AND_ASSIGN(MockPrinter);
 };
 
 #endif  // CHROME_RENDERER_MOCK_PRINTER_H_