RefCounted types should not have public destructors, chrome/ remaining parts

chrome/service/cloud_print/print_system_win.cc

Index: chrome/service/cloud_print/print_system_win.cc
diff --git a/chrome/service/cloud_print/print_system_win.cc b/chrome/service/cloud_print/print_system_win.cc
index b9d5c528be9a5851146e0b7768c0505ba82db79f..7ae902c48b65278137fcf9f0ec206c258a26b380 100644
--- a/chrome/service/cloud_print/print_system_win.cc
+++ b/chrome/service/cloud_print/print_system_win.cc
@@ -290,6 +290,9 @@ class PrintSystemWin : public PrintSystem {
     virtual void OnPrinterChanged() OVERRIDE {}
     virtual void OnJobChanged() OVERRIDE {}
 
+   protected:
+    virtual ~PrintServerWatcherWin() {}
+
    private:
     PrintSystem::PrintServerWatcher::Delegate* delegate_;
     PrintSystemWatcherWin watcher_;
@@ -338,6 +341,9 @@ class PrintSystemWin : public PrintSystem {
       delegate_->OnJobChanged();
     }
 
+   protected:
+    virtual ~PrinterWatcherWin() {}
+
    private:
     std::string printer_name_;
     PrintSystem::PrinterWatcher::Delegate* delegate_;
@@ -368,6 +374,9 @@ class PrintSystemWin : public PrintSystem {
                           delegate);
     }
 
+   protected:
+    virtual ~JobSpoolerWin() {}
+
    private:
     // We use a Core class because we want a separate RefCountedThreadSafe
     // implementation for ServiceUtilityProcessHost::Client.