Standardize usage of virtual/override/final in base/

base/synchronization/waitable_event_watcher.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 BASE_SYNCHRONIZATION_WAITABLE_EVENT_WATCHER_H_
 #define BASE_SYNCHRONIZATION_WAITABLE_EVENT_WATCHER_H_
 
 #include "base/base_export.h"
 #include "build/build_config.h"
 
@@ skipping 49 matching lines @@
 
 class BASE_EXPORT WaitableEventWatcher
 #if defined(OS_WIN)
     : public win::ObjectWatcher::Delegate {
 #else
     : public MessageLoop::DestructionObserver {
 #endif
  public:
   typedef Callback<void(WaitableEvent*)> EventCallback;
   WaitableEventWatcher();
-  virtual ~WaitableEventWatcher();
+  ~WaitableEventWatcher() override;
 
   // When @event is signaled, the given callback is called on the thread of the
   // current message loop when StartWatching is called.
   bool StartWatching(WaitableEvent* event, const EventCallback& callback);
 
   // Cancel the current watch. Must be called from the same thread which
   // started the watch.
   //
   // Does nothing if no event is being watched, nor if the watch has completed.
   // The callback will *not* be called for the current watch after this
   // function returns. Since the callback runs on the same thread as this
   // function, it cannot be called during this function either.
   void StopWatching();
 
   // Return the currently watched event, or NULL if no object is currently being
   // watched.
   WaitableEvent* GetWatchedEvent();
 
   // Return the callback that will be invoked when the event is
   // signaled.
   const EventCallback& callback() const { return callback_; }
 
  private:
 #if defined(OS_WIN)
   virtual void OnObjectSignaled(HANDLE h) override;
   win::ObjectWatcher watcher_;
 #else
   // Implementation of MessageLoop::DestructionObserver
-  virtual void WillDestroyCurrentMessageLoop() override;
+  void WillDestroyCurrentMessageLoop() override;
 
   MessageLoop* message_loop_;
   scoped_refptr<Flag> cancel_flag_;
   AsyncWaiter* waiter_;
   base::Closure internal_callback_;
   scoped_refptr<WaitableEvent::WaitableEventKernel> kernel_;
 #endif
 
   WaitableEvent* event_;
   EventCallback callback_;
 };
 
 }  // namespace base
 
 #endif  // BASE_SYNCHRONIZATION_WAITABLE_EVENT_WATCHER_H_