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

chrome/service/cloud_print/print_system.h

Index: chrome/service/cloud_print/print_system.h
diff --git a/chrome/service/cloud_print/print_system.h b/chrome/service/cloud_print/print_system.h
index f1ba32409f8885edd22a7f642265224fc94d942f..00b2141df61907c34cceae2e1e2020c594d6d281 100644
--- a/chrome/service/cloud_print/print_system.h
+++ b/chrome/service/cloud_print/print_system.h
@@ -84,9 +84,12 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
         virtual ~Delegate() {}
     };
 
-    virtual ~PrintServerWatcher();
     virtual bool StartWatching(PrintServerWatcher::Delegate* delegate) = 0;
     virtual bool StopWatching() = 0;
+
+   protected:
+    friend class base::RefCountedThreadSafe<PrintServerWatcher>;
+    virtual ~PrintServerWatcher();
   };
 
   class PrinterWatcher : public base::RefCountedThreadSafe<PrinterWatcher> {
@@ -102,11 +105,14 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
         virtual ~Delegate() {}
     };
 
-    virtual ~PrinterWatcher();
     virtual bool StartWatching(PrinterWatcher::Delegate* delegate) = 0;
     virtual bool StopWatching() = 0;
     virtual bool GetCurrentPrinterInfo(
         printing::PrinterBasicInfo* printer_info) = 0;
+
+   protected:
+    friend class base::RefCountedThreadSafe<PrinterWatcher>;
+    virtual ~PrinterWatcher();
   };
 
   class JobSpooler : public base::RefCountedThreadSafe<JobSpooler> {
@@ -119,7 +125,6 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
         virtual void OnJobSpoolFailed() = 0;
     };
 
-    virtual ~JobSpooler();
     // 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
@@ -131,6 +136,9 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
                        const std::string& job_title,
                        const std::vector<std::string>& tags,
                        JobSpooler::Delegate* delegate) = 0;
+   protected:
+    friend class base::RefCountedThreadSafe<JobSpooler>;
+    virtual ~JobSpooler();
   };
 
   class PrintSystemResult {
@@ -152,8 +160,6 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
                               const printing::PrinterCapsAndDefaults&)>
       PrinterCapsAndDefaultsCallback;
 
-  virtual ~PrintSystem();
-
   // Initialize print system. This need to be called before any other function
   // of PrintSystem.
   virtual PrintSystemResult Init() = 0;
@@ -199,6 +205,10 @@ class PrintSystem : public base::RefCountedThreadSafe<PrintSystem> {
   // Return NULL if no print system available.
   static scoped_refptr<PrintSystem> CreateInstance(
       const base::DictionaryValue* print_system_settings);
+
+ protected:
+  friend class base::RefCountedThreadSafe<PrintSystem>;
+  virtual ~PrintSystem();
 };