Revert of Standardize usage of virtual/override/final in ipc/

ipc/ipc_sync_message.h

 // Copyright (c) 2012 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_MESSAGE_H_
 #define IPC_IPC_SYNC_MESSAGE_H_
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 #include <string>
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ipc/ipc_message.h"
 
 namespace base {
 class WaitableEvent;
 }
 
 namespace IPC {
 
 class MessageReplyDeserializer;
 
 class IPC_EXPORT SyncMessage : public Message {
  public:
   SyncMessage(int32 routing_id, uint32 type, PriorityValue priority,
               MessageReplyDeserializer* deserializer);
-  ~SyncMessage() override;
+  virtual ~SyncMessage();
 
   // Call this to get a deserializer for the output parameters.
   // Note that this can only be called once, and the caller is responsible
   // for deleting the deserializer when they're done.
   MessageReplyDeserializer* GetReplyDeserializer();
 
   // If this message can cause the receiver to block while waiting for user
   // input (i.e. by calling MessageBox), then the caller needs to pump window
   // messages and dispatch asynchronous messages while waiting for the reply.
   // If this event is passed in, then window messages will start being pumped
@@ skipping 63 matching lines @@
       : id(id), deserializer(d), done_event(e), send_result(false) { }
   int id;
   MessageReplyDeserializer* deserializer;
   base::WaitableEvent* done_event;
   bool send_result;
 };
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_SYNC_MESSAGE_H_