Virtual destructors should have virtual keyword.

ipc/ipc_test_sink.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 IPC_IPC_TEST_SINK_H_
 #define IPC_IPC_TEST_SINK_H_
 #pragma once
 
 #include <utility>
 #include <vector>
@@ skipping 56 matching lines @@
 //   StartSomeAsynchronousProcess(&test_sink);
 //   MessageLoop::current()->Run();
 //   <inspect the results>
 //   ...
 //
 // To hook up the sink, all you need to do is call OnMessageReceived when a
 // message is received.
 class TestSink : public Channel {
  public:
   TestSink();
-  ~TestSink();
+  virtual ~TestSink();
 
   // Interface in IPC::Channel. This copies the message to the sink and then
   // deletes it.
   virtual bool Send(IPC::Message* message);
 
   // Used by the source of the messages to send the message to the sink. This
   // will make a copy of the message and store it in the list.
   bool OnMessageReceived(const Message& msg);
 
   // Returns the number of messages in the queue.
@@ skipping 33 matching lines @@
   // The actual list of received messages.
   std::vector<Message> messages_;
   ObserverList<Channel::Listener> filter_list_;
 
   DISALLOW_COPY_AND_ASSIGN(TestSink);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_TEST_SINK_H_