Virtual destructors should have virtual keyword.

chrome/browser/debugger/devtools_netlog_observer.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_BROWSER_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_
 #define CHROME_BROWSER_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_
 #pragma once
 
 #include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
@@ skipping 49 matching lines @@
   // Must be called on the IO thread. May return NULL if no observers
   // are active.
   static DevToolsNetLogObserver* GetInstance();
   static void PopulateResponseInfo(net::URLRequest*, ResourceResponse*);
   static int GetAndResetEncodedDataLength(net::URLRequest* request);
 
  private:
   static DevToolsNetLogObserver* instance_;
 
   explicit DevToolsNetLogObserver(ChromeNetLog* chrome_net_log);
-  ~DevToolsNetLogObserver();
+  virtual ~DevToolsNetLogObserver();
 
   ResourceInfo* GetResourceInfo(uint32 id);
 
   ChromeNetLog* chrome_net_log_;
   typedef base::hash_map<uint32, scoped_refptr<ResourceInfo> > RequestToInfoMap;
   typedef base::hash_map<uint32, int> RequestToEncodedDataLengthMap;
   typedef base::hash_map<uint32, uint32> HTTPStreamJobToSocketMap;
   typedef base::hash_map<uint32, uint32> SocketToRequestMap;
   RequestToInfoMap request_to_info_;
   RequestToEncodedDataLengthMap request_to_encoded_data_length_;
   HTTPStreamJobToSocketMap http_stream_job_to_socket_;
   SocketToRequestMap socket_to_request_;
 
   DISALLOW_COPY_AND_ASSIGN(DevToolsNetLogObserver);
 };
 
 #endif  // CHROME_BROWSER_DEBUGGER_DEVTOOLS_NETLOG_OBSERVER_H_