RefCounted types should not have public destructors, delegate cleanup

chrome/service/cloud_print/print_system.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 CHROME_SERVICE_CLOUD_PRINT_PRINT_SYSTEM_H_
 #define CHROME_SERVICE_CLOUD_PRINT_PRINT_SYSTEM_H_
 #pragma once
 
 #include <map>
 #include <string>
@@ skipping 101 matching lines @@
 
    protected:
     friend class base::RefCountedThreadSafe<PrinterWatcher>;
     virtual ~PrinterWatcher();
   };
 
   class JobSpooler : public base::RefCountedThreadSafe<JobSpooler> {
    public:
     // Callback interface for JobSpooler notifications.
     class Delegate {
-      public:
-        virtual ~Delegate() { }
-        virtual void OnJobSpoolSucceeded(const PlatformJobId& job_id) = 0;
-        virtual void OnJobSpoolFailed() = 0;
+     public:
+      virtual void OnJobSpoolSucceeded(const PlatformJobId& job_id) = 0;
+      virtual void OnJobSpoolFailed() = 0;
+
+     protected:
+      virtual ~Delegate() {}
     };
 
     // Spool job to the printer asynchronously. Caller will be notified via
     // |delegate|. Note that only one print job can be in progress at any given
     // time. Subsequent calls to Spool (before the Delegate::OnJobSpoolSucceeded
     // or Delegate::OnJobSpoolFailed methods are called) can fail.
     virtual bool Spool(const std::string& print_ticket,
                        const FilePath& print_data_file_path,
                        const std::string& print_data_mime_type,
                        const std::string& printer_name,
@@ skipping 80 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_