RefCounted types should not have public destructors, net/

net/base/address_list_net_log_param.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 NET_BASE_ADDRESS_LIST_NET_LOG_PARAM_H_
 #define NET_BASE_ADDRESS_LIST_NET_LOG_PARAM_H_
 #pragma once
 
 #include "net/base/address_list.h"
 #include "net/base/net_log.h"
 
 namespace net {
 
 // NetLog parameter to describe an address list.
 // Note that AddressList uses ref-counted data, so this doesn't introduce
 // much of a memory overhead.
 class AddressListNetLogParam : public NetLog::EventParameters {
  public:
   explicit AddressListNetLogParam(const AddressList& address_list);
 
   virtual base::Value* ToValue() const OVERRIDE;
 
+ protected:
+  virtual ~AddressListNetLogParam() {}
+
  private:
   AddressList address_list_;
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_ADDRESS_LIST_NET_LOG_PARAM_H_