RefCounted types should not have public destructors, base/ edition

base/threading/non_thread_safe.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 BASE_THREADING_NON_THREAD_SAFE_H_
 #define BASE_THREADING_NON_THREAD_SAFE_H_
 #pragma once
 
 // Classes deriving from NonThreadSafe may need to supress MSVC warning 4275:
 // non dll-interface class 'Bar' used as base for dll-interface class 'Foo'.
@@ skipping 11 matching lines @@
 //
 // Note: You should almost always use the NonThreadSafe class to get
 // the right version of the class for your build configuration.
 class NonThreadSafeDoNothing {
  public:
   bool CalledOnValidThread() const {
     return true;
   }
 
  protected:
+  ~NonThreadSafeDoNothing() {}
   void DetachFromThread() {}
 };
 
 // NonThreadSafe is a helper class used to help verify that methods of a
 // class are called from the same thread.  One can inherit from this class
 // and use CalledOnValidThread() to verify.
 //
 // This is intended to be used with classes that appear to be thread safe, but
 // aren't.  For example, a service or a singleton like the preferences system.
 //
 // Example:
 // class MyClass : public base::NonThreadSafe {
 //  public:
 //   void Foo() {
 //     DCHECK(CalledOnValidThread());
 //     ... (do stuff) ...
 //   }
 // }
 //
 // In Release mode, CalledOnValidThread will always return true.
 //
 #ifndef NDEBUG
-class NonThreadSafe : public NonThreadSafeImpl {
-};
+typedef NonThreadSafeImpl NonThreadSafe;
 #else
-class NonThreadSafe : public NonThreadSafeDoNothing {
-};
+typedef NonThreadSafeDoNothing NonThreadSafe;
 #endif  // NDEBUG
 
 }  // namespace base
 
 #endif  // BASE_NON_THREAD_SAFE_H_