RefCounted types should not have public destructors, base/ edition

base/memory/ref_counted.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 BASE_MEMORY_REF_COUNTED_H_
 #define BASE_MEMORY_REF_COUNTED_H_
 #pragma once
 
 #include <cassert>
 
@@ skipping 67 matching lines @@
 //    private:
 //     friend class base::RefCounted<MyFoo>;
 //     ~MyFoo();
 //   };
 //
 // You should always make your destructor private, to avoid any code deleting
 // the object accidently while there are references to it.
 template <class T>
 class RefCounted : public subtle::RefCountedBase {
  public:
-  RefCounted() { }
-  ~RefCounted() { }
+  RefCounted() {}
 
   void AddRef() const {
     subtle::RefCountedBase::AddRef();
   }
 
   void Release() const {
     if (subtle::RefCountedBase::Release()) {
       delete static_cast<const T*>(this);
     }
   }
 
+ protected:
+  ~RefCounted() {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(RefCounted<T>);
 };
 
 // Forward declaration.
 template <class T, typename Traits> class RefCountedThreadSafe;
 
 // Default traits for RefCountedThreadSafe<T>.  Deletes the object when its ref
 // count reaches 0.  Overload to delete it on a different thread etc.
 template<typename T>
@@ skipping 15 matching lines @@
 //   };
 //
 // If you're using the default trait, then you should add compile time
 // asserts that no one else is deleting your object.  i.e.
 //    private:
 //     friend class base::RefCountedThreadSafe<MyFoo>;
 //     ~MyFoo();
 template <class T, typename Traits = DefaultRefCountedThreadSafeTraits<T> >
 class RefCountedThreadSafe : public subtle::RefCountedThreadSafeBase {
  public:
-  RefCountedThreadSafe() { }
-  ~RefCountedThreadSafe() { }
+  RefCountedThreadSafe() {}
 
   void AddRef() const {
     subtle::RefCountedThreadSafeBase::AddRef();
   }
 
   void Release() const {
     if (subtle::RefCountedThreadSafeBase::Release()) {
       Traits::Destruct(static_cast<const T*>(this));
     }
   }
 
+ protected:
+  ~RefCountedThreadSafe() {}
+
  private:
   friend struct DefaultRefCountedThreadSafeTraits<T>;
   static void DeleteInternal(const T* x) { delete x; }
 
   DISALLOW_COPY_AND_ASSIGN(RefCountedThreadSafe);
 };
 
 //
 // A wrapper for some piece of data so we can place other things in
 // scoped_refptrs<>.
@@ skipping 143 matching lines @@
 };
 
 // Handy utility for creating a scoped_refptr<T> out of a T* explicitly without
 // having to retype all the template arguments
 template <typename T>
 scoped_refptr<T> make_scoped_refptr(T* t) {
   return scoped_refptr<T>(t);
 }
 
 #endif  // BASE_MEMORY_REF_COUNTED_H_