Virtual destructors should have virtual keyword.

net/disk_cache/entry_impl.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_DISK_CACHE_ENTRY_IMPL_H_
 #define NET_DISK_CACHE_ENTRY_IMPL_H_
 #pragma once
 
 #include "base/memory/scoped_ptr.h"
 #include "net/base/net_log.h"
@@ skipping 134 matching lines @@
   virtual bool CouldBeSparse() const;
   virtual void CancelSparseIO();
   virtual int ReadyForSparseIO(net::CompletionCallback* completion_callback);
 
  private:
   enum {
      kNumStreams = 3
   };
   class UserBuffer;
 
-  ~EntryImpl();
+  virtual ~EntryImpl();
 
   // Do all the work for ReadDataImpl and WriteDataImpl.  Implemented as
   // separate functions to make logging of results simpler.
   int InternalReadData(int index, int offset, net::IOBuffer* buf,
                        int buf_len, CompletionCallback* callback);
   int InternalWriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
                         CompletionCallback* callback, bool truncate);
 
   // Initializes the storage for an internal or external data block.
   bool CreateDataBlock(int index, int size);
@@ skipping 80 matching lines @@
   scoped_ptr<SparseControl> sparse_;  // Support for sparse entries.
 
   net::BoundNetLog net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(EntryImpl);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_ENTRY_IMPL_H_