Virtual destructors should have virtual keyword.

net/disk_cache/mem_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_MEM_ENTRY_IMPL_H_
 #define NET_DISK_CACHE_MEM_ENTRY_IMPL_H_
 #pragma once
 
 #include "base/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 102 matching lines @@
   virtual void CancelSparseIO() {}
   virtual int ReadyForSparseIO(net::CompletionCallback* completion_callback);
 
  private:
   typedef base::hash_map<int, MemEntryImpl*> EntryMap;
 
   enum {
     NUM_STREAMS = 3
   };
 
-  ~MemEntryImpl();
+  virtual ~MemEntryImpl();
 
   // Do all the work for corresponding public functions.  Implemented as
   // separate functions to make logging of results simpler.
   int InternalReadData(int index, int offset, net::IOBuffer* buf, int buf_len);
   int InternalWriteData(int index, int offset, net::IOBuffer* buf, int buf_len,
                         bool truncate);
   int InternalReadSparseData(int64 offset, net::IOBuffer* buf, int buf_len);
   int InternalWriteSparseData(int64 offset, net::IOBuffer* buf, int buf_len);
 
   // Old Entry interface.
@@ skipping 47 matching lines @@
   bool doomed_;               // True if this entry was removed from the cache.
 
   net::BoundNetLog net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(MemEntryImpl);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_MEM_ENTRY_IMPL_H_