Standardize usage of virtual/override/final in net/

net/dns/notify_watcher_mac.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 NET_DNS_NOTIFY_WATCHER_MAC_H_
 #define NET_DNS_NOTIFY_WATCHER_MAC_H_
 
 #include "base/callback.h"
 #include "base/message_loop/message_loop.h"
 
 namespace net {
 
 // Watches for notifications from Libnotify and delivers them to a Callback.
 // After failure the watch is cancelled and will have to be restarted.
 class NotifyWatcherMac : public base::MessageLoopForIO::Watcher {
  public:
   // Called on received notification with true on success and false on error.
   typedef base::Callback<void(bool succeeded)> CallbackType;
 
   NotifyWatcherMac();
 
   // When deleted, automatically cancels.
-  virtual ~NotifyWatcherMac();
+  ~NotifyWatcherMac() override;
 
   // Registers for notifications for |key|. Returns true if succeeds. If so,
   // will deliver asynchronous notifications and errors to |callback|.
   bool Watch(const char* key, const CallbackType& callback);
 
   // Cancels the watch.
   void Cancel();
 
  private:
   // MessageLoopForIO::Watcher:
-  virtual void OnFileCanReadWithoutBlocking(int fd) override;
-  virtual void OnFileCanWriteWithoutBlocking(int fd) override {}
+  void OnFileCanReadWithoutBlocking(int fd) override;
+  void OnFileCanWriteWithoutBlocking(int fd) override {}
 
   int notify_fd_;
   int notify_token_;
   CallbackType callback_;
   base::MessageLoopForIO::FileDescriptorWatcher watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(NotifyWatcherMac);
 };
 
 }  // namespace net
 
 #endif  // NET_DNS_NOTIFY_WATCHER_MAC_H_