Virtual destructors should have virtual keyword.

net/socket/client_socket_pool_base.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.
 //
 // A ClientSocketPoolBase is used to restrict the number of sockets open at
 // a time.  It also maintains a list of idle persistent sockets for reuse.
 // Subclasses of ClientSocketPool should compose ClientSocketPoolBase to handle
 // the core logic of (1) restricting the number of active (connected or
 // connecting) sockets per "group" (generally speaking, the hostname), (2)
 // maintaining a per-group list of idle, persistent sockets for reuse, and (3)
@@ skipping 201 matching lines @@
     DISALLOW_COPY_AND_ASSIGN(ConnectJobFactory);
   };
 
   ClientSocketPoolBaseHelper(
       int max_sockets,
       int max_sockets_per_group,
       base::TimeDelta unused_idle_socket_timeout,
       base::TimeDelta used_idle_socket_timeout,
       ConnectJobFactory* connect_job_factory);
 
-  ~ClientSocketPoolBaseHelper();
+  virtual ~ClientSocketPoolBaseHelper();
 
   // See ClientSocketPool::RequestSocket for documentation on this function.
   // ClientSocketPoolBaseHelper takes ownership of |request|, which must be
   // heap allocated.
   int RequestSocket(const std::string& group_name, const Request* request);
 
   // See ClientSocketPool::RequestSocket for documentation on this function.
   void RequestSockets(const std::string& group_name,
                       const Request& request,
                       int num_sockets);
@@ skipping 513 matching lines @@
   // Histograms for the pool
   ClientSocketPoolHistograms* const histograms_;
   internal::ClientSocketPoolBaseHelper helper_;
 
   DISALLOW_COPY_AND_ASSIGN(ClientSocketPoolBase);
 };
 
 }  // namespace net
 
 #endif  // NET_SOCKET_CLIENT_SOCKET_POOL_BASE_H_