RefCounted types should not have public destructors, delegate cleanup

content/renderer/media/scoped_loop_observer.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 CONTENT_RENDERER_MEDIA_SCOPED_LOOP_OBSERVER_H_
 #define CONTENT_RENDERER_MEDIA_SCOPED_LOOP_OBSERVER_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 
 namespace base {
 class WaitableEvent;
 }
 
 // A common base class for AudioDevice and AudioInputDevice that manages
 // a message loop pointer and monitors it for destruction. If the object goes
 // out of scope before the message loop, the object will automatically remove
 // itself from the message loop's list of destruction observers.
 // NOTE: The class that inherits from this class must implement the
 // WillDestroyCurrentMessageLoop virtual method from DestructionObserver.
 class ScopedLoopObserver
     : public MessageLoop::DestructionObserver {
  public:
   explicit ScopedLoopObserver(MessageLoop* message_loop);
+
+ protected:
   virtual ~ScopedLoopObserver();
 
- protected:
   // Accessor to the loop that's used by the derived class.
   base::MessageLoopProxy* message_loop() { return loop_; }
 
  private:
   // Call to add or remove ourselves from the list of destruction observers for
   // the message loop.
   void ObserveLoopDestruction(bool enable, base::WaitableEvent* done);
 
   // A pointer to the message loop's proxy. In case the loop gets destroyed
   // before this object goes out of scope, PostTask etc will fail but not crash.
   scoped_refptr<base::MessageLoopProxy> loop_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedLoopObserver);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_SCOPED_LOOP_OBSERVER_H_