Virtual destructors should have virtual keyword.

net/disk_cache/in_flight_backend_io.h

 // Copyright (c) 2010 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_DISK_CACHE_IN_FLIGHT_BACKEND_IO_H_
 #define NET_DISK_CACHE_IN_FLIGHT_BACKEND_IO_H_
 #pragma once
 
 #include <list>
 #include <string>
@@ skipping 85 matching lines @@
     OP_MAX_BACKEND,
     OP_READ,
     OP_WRITE,
     OP_READ_SPARSE,
     OP_WRITE_SPARSE,
     OP_GET_RANGE,
     OP_CANCEL_IO,
     OP_IS_READY
   };
 
-  ~BackendIO();
+  virtual ~BackendIO();
 
   void ExecuteBackendOperation();
   void ExecuteEntryOperation();
 
   BackendImpl* backend_;
   net::CompletionCallback* callback_;
   Operation operation_;
   net::CompletionCallbackImpl<BackendIO> my_callback_;
 
   // The arguments of all the operations we proxy:
@@ skipping 15 matching lines @@
   Task* task_;
 
   DISALLOW_COPY_AND_ASSIGN(BackendIO);
 };
 
 // The specialized controller that keeps track of current operations.
 class InFlightBackendIO : public InFlightIO {
  public:
   InFlightBackendIO(BackendImpl* backend,
                     base::MessageLoopProxy* background_thread);
-  ~InFlightBackendIO();
+  virtual ~InFlightBackendIO();
 
   // The operations we proxy:
   void Init(net::CompletionCallback* callback);
   void OpenEntry(const std::string& key, Entry** entry,
                  net::CompletionCallback* callback);
   void CreateEntry(const std::string& key, Entry** entry,
                    net::CompletionCallback* callback);
   void DoomEntry(const std::string& key, net::CompletionCallback* callback);
   void DoomAllEntries(net::CompletionCallback* callback);
   void DoomEntriesBetween(const base::Time initial_time,
@@ skipping 43 matching lines @@
 
   BackendImpl* backend_;
   scoped_refptr<base::MessageLoopProxy> background_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(InFlightBackendIO);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_IN_FLIGHT_BACKEND_IO_H_