Added a diagnostic user message when enumerating printers fails. Also tweaked...

chrome/service/cloud_print/print_system_win.cc

 // Copyright (c) 2010 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.
 
 #include "chrome/service/cloud_print/print_system.h"
 
 #include <objidl.h>
 #include <winspool.h>
 
 #include "base/file_path.h"
@@ skipping 232 matching lines @@
 // PrintSystemWin watchers from wrong Delegate, giving C2664 and C2259 errors.
 typedef PrintSystemWatcherWin::Delegate PrintSystemWatcherWinDelegate;
 
 class PrintSystemWin : public PrintSystem {
  public:
   PrintSystemWin();
 
   // PrintSystem implementation.
   virtual PrintSystemResult Init();
 
-  virtual void EnumeratePrinters(printing::PrinterList* printer_list);
+  virtual PrintSystem::PrintSystemResult EnumeratePrinters(
+      printing::PrinterList* printer_list);
 
   virtual void GetPrinterCapsAndDefaults(
       const std::string& printer_name,
       PrinterCapsAndDefaultsCallback* callback);
 
   virtual bool IsValidPrinter(const std::string& printer_name);
 
   virtual bool ValidatePrintTicket(const std::string& printer_name,
                                    const std::string& print_ticket_data);
 
@@ skipping 334 matching lines @@
 
 PrintSystem::PrintSystemResult PrintSystemWin::Init() {
   if (!printing::XPSModule::Init()) {
     std::string message = l10n_util::GetStringUTF8(
         IDS_CLOUD_PRINT_XPS_UNAVAILABLE);
     return PrintSystemResult(false, message);
   }
   return PrintSystemResult(true, std::string());
 }
 
-void PrintSystemWin::EnumeratePrinters(printing::PrinterList* printer_list) {
-  print_backend_->EnumeratePrinters(printer_list);
+PrintSystem::PrintSystemResult PrintSystemWin::EnumeratePrinters(
+    printing::PrinterList* printer_list) {
+  bool ret = print_backend_->EnumeratePrinters(printer_list);
+  return PrintSystemResult(ret, std::string());
 }
 
 void PrintSystemWin::GetPrinterCapsAndDefaults(
     const std::string& printer_name,
     PrinterCapsAndDefaultsCallback* callback) {
   // Launch as child process to retrieve the capabilities and defaults because
   // this involves invoking a printer driver DLL and crashes have been known to
   // occur.
   PrinterCapsHandler* handler =
       new PrinterCapsHandler(printer_name, callback);
@@ skipping 117 matching lines @@
   RpcStringFree(reinterpret_cast<RPC_WSTR *>(&proxy_id_as_string));
   return ret;
 }
 
 scoped_refptr<PrintSystem> PrintSystem::CreateInstance(
     const DictionaryValue* print_system_settings) {
   return new PrintSystemWin;
 }
 
 }  // namespace cloud_print