RefCounted types should not have public destructors, delegate cleanup

chrome/common/net/gaia/oauth2_access_token_consumer.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 CHROME_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_CONSUMER_H_
 #define CHROME_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_CONSUMER_H_
 #pragma once
 
 #include <string>
 
 class GoogleServiceAuthError;
 
 // An interface that defines the callbacks for consumers to which
 // OAuth2AccessTokenFetcher can return results.
 class OAuth2AccessTokenConsumer {
  public:
-  virtual ~OAuth2AccessTokenConsumer() {}
-
   virtual void OnGetTokenSuccess(const std::string& access_token) {}
   virtual void OnGetTokenFailure(const GoogleServiceAuthError& error) {}
+
+ protected:
+  virtual ~OAuth2AccessTokenConsumer() {}
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_OAUTH2_ACCESS_TOKEN_CONSUMER_H_