ScopedPrinterInfoSetter on crash prone blocks.

printing/backend/print_backend.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_BACKEND_PRINT_BACKEND_H_
 #define PRINTING_BACKEND_PRINT_BACKEND_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 49 matching lines @@
 
   // Get the default printer name. Empty string if no default printer.
   virtual std::string GetDefaultPrinterName() = 0;
 
   // Gets the capabilities and defaults for a specific printer.
   virtual bool GetPrinterCapsAndDefaults(
       const std::string& printer_name,
       PrinterCapsAndDefaults* printer_info) = 0;
 
   // Gets the information about driver for a specific printer.
-  virtual bool GetPrinterDriverInfo(
-      const std::string& printer_name,
-      std::string* driver_info) = 0;
+  virtual std::string GetPrinterDriverInfo(
+      const std::string& printer_name) = 0;
 
   // Returns true if printer_name points to a valid printer.
   virtual bool IsValidPrinter(const std::string& printer_name) = 0;
 
   // Allocate a print backend. If |print_backend_settings| is NULL, default
   // settings will be used.
   // Return NULL if no print backend available.
   static scoped_refptr<PrintBackend> CreateInstance(
       const base::DictionaryValue* print_backend_settings);
 };
 
 }  // namespace printing
 
 #endif  // PRINTING_BACKEND_PRINT_BACKEND_H_