Virtual destructors should have virtual keyword.

ipc/ipc_sync_channel.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_SYNC_SENDER_H__
 #define IPC_IPC_SYNC_SENDER_H__
 #pragma once
 
 #include <string>
 #include <deque>
@@ skipping 123 matching lines @@
     base::WaitableEvent* shutdown_event() { return shutdown_event_; }
 
     ReceivedSyncMsgQueue* received_sync_msgs() {
       return received_sync_msgs_;
     }
 
     void set_restrict_dispatch(bool value) { restrict_dispatch_ = value; }
     bool restrict_dispatch() const { return restrict_dispatch_; }
 
    private:
-    ~SyncContext();
+    virtual ~SyncContext();
     // ChannelProxy methods that we override.
 
     // Called on the listener thread.
     virtual void Clear();
 
     // Called on the IPC thread.
     virtual bool OnMessageReceived(const Message& msg);
     virtual void OnChannelError();
     virtual void OnChannelOpened();
     virtual void OnChannelClosed();
@@ skipping 36 matching lines @@
 
   // Used to signal events between the IPC and listener threads.
   base::WaitableEventWatcher dispatch_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncChannel);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_SYNC_SENDER_H__