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

ipc/ipc_channel.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_CHANNEL_H_
 #define IPC_IPC_CHANNEL_H_
 
 #include <string>
 
 #if defined(OS_POSIX)
@@ skipping 125 matching lines @@
 #if defined(OS_POSIX)
   // An "open" named server accepts connections from ANY client.
   // The caller must then implement their own access-control based on the
   // client process' user Id.
   static scoped_ptr<Channel> CreateOpenNamedServer(
       const IPC::ChannelHandle &channel_handle, Listener* listener);
 #endif
   static scoped_ptr<Channel> CreateServer(
       const IPC::ChannelHandle &channel_handle, Listener* listener);
 
-  ~Channel() override;
+
+  virtual ~Channel();
 
   // Connect the pipe.  On the server side, this will initiate
   // waiting for connections.  On the client, it attempts to
   // connect to a pre-existing pipe.  Note, calling Connect()
   // will not block the calling thread and may complete
   // asynchronously.
   virtual bool Connect() WARN_UNUSED_RESULT = 0;
 
   // Close this Channel explicitly.  May be called multiple times.
   // On POSIX calling close on an IPC channel that listens for connections will
@@ skipping 69 matching lines @@
 
 #if defined(OS_POSIX)
 // SocketPair() creates a pair of socket FDs suitable for using with
 // IPC::Channel.
 IPC_EXPORT bool SocketPair(int* fd1, int* fd2);
 #endif
 
 }  // namespace IPC
 
 #endif  // IPC_IPC_CHANNEL_H_