Fix win style errors.

ipc/attachment_broker_win.h

 // Copyright 2015 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_ATTACHMENT_BROKER_WIN_H_
 #define IPC_ATTACHMENT_BROKER_WIN_H_
 
 #include "ipc/attachment_broker.h"
 #include "ipc/ipc_export.h"
 #include "ipc/ipc_sender.h"
 
 namespace IPC {
 
 // This class is an implementation of AttachmentBroker for the Windows platform.
 class IPC_EXPORT AttachmentBrokerWin : public IPC::AttachmentBroker {
  public:
   AttachmentBrokerWin();
-  virtual ~AttachmentBrokerWin();
+  ~AttachmentBrokerWin() override;
 
   // In a non-broker process, the single instance of this class listens for
   // an IPC from the broker process indicating that a new attachment has been
   // duplicated.
   void OnReceiveDuplicatedHandle(HANDLE, BrokerableAttachment::AttachmentId id);
 
   // IPC::AttachmentBroker overrides.
   void SendAttachmentToProcess(BrokerableAttachment* attachment,
                                base::ProcessId destination_process) override;
   bool GetAttachmentWithId(BrokerableAttachment::AttachmentId id,
                            BrokerableAttachment* attachment) override;
 };
 
 }  // namespace IPC
 
 #endif  // IPC_ATTACHMENT_BROKER_WIN_H_