iwyu: Use callback_old.h where appropriate, part 2.

chrome/service/cloud_print/print_system.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_SERVICE_CLOUD_PRINT_PRINT_SYSTEM_H_
 #define CHROME_SERVICE_CLOUD_PRINT_PRINT_SYSTEM_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
-#include "base/callback.h"
+#include "base/callback_old.h"
 #include "base/memory/ref_counted.h"
 
 #include "printing/backend/print_backend.h"
 
 class DictionaryValue;
 class FilePath;
 
 namespace printing {
 class PrintBackend;
 struct PrinterBasicInfo;
@@ skipping 181 matching lines @@
 // Visual Studio where it gets confused between multiple Delegate
 // classes and gives a C2500 error. (I saw this error on the try bots -
 // the workaround was not needed for my machine).
 typedef PrintSystem::PrintServerWatcher::Delegate PrintServerWatcherDelegate;
 typedef PrintSystem::PrinterWatcher::Delegate PrinterWatcherDelegate;
 typedef PrintSystem::JobSpooler::Delegate JobSpoolerDelegate;
 
 }  // namespace cloud_print
 
 #endif  // CHROME_SERVICE_CLOUD_PRINT_PRINT_SYSTEM_H_