Standardize usage of virtual/override/final in ipc/

ipc/ipc_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_MESSAGE_H_
 #define IPC_IPC_MESSAGE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 32 matching lines @@
   enum {
     PRIORITY_MASK     = 0x03,  // Low 2 bits of store the priority value.
     SYNC_BIT          = 0x04,
     REPLY_BIT         = 0x08,
     REPLY_ERROR_BIT   = 0x10,
     UNBLOCK_BIT       = 0x20,
     PUMPING_MSGS_BIT  = 0x40,
     HAS_SENT_TIME_BIT = 0x80,
   };
 
-  virtual ~Message();
+  ~Message() override;
 
   Message();
 
   // Initialize a message with a user-defined type, priority value, and
   // destination WebView ID.
   Message(int32 routing_id, uint32 type, PriorityValue priority);
 
   // Initializes a message from a const block of data.  The data is not copied;
   // instead the data is merely referenced by this message.  Only const methods
   // should be used on the message when initialized this way.
@@ skipping 220 matching lines @@
   MSG_ROUTING_NONE = -2,
 
   // indicates a general message not sent to a particular tab.
   MSG_ROUTING_CONTROL = kint32max,
 };
 
 #define IPC_REPLY_ID 0xFFFFFFF0  // Special message id for replies
 #define IPC_LOGGING_ID 0xFFFFFFF1  // Special message id for logging
 
 #endif  // IPC_IPC_MESSAGE_H_