Update {virtual,override} to follow C++11 style in ui.

ui/events/event_target_iterator.h

 // Copyright 2013 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 UI_EVENTS_EVENT_TARGET_ITERATOR_H_
 #define UI_EVENTS_EVENT_TARGET_ITERATOR_H_
 
 #include <vector>
 
 namespace ui {
@@ skipping 10 matching lines @@
 // Provides an EventTargetIterator implementation for iterating over a list of
 // EventTargets. The list is iterated in the reverse order, since typically the
 // EventTargets are maintained in increasing z-order in the lists.
 template<typename T>
 class EventTargetIteratorImpl : public EventTargetIterator {
  public:
   explicit EventTargetIteratorImpl(const std::vector<T*>& children)
       : begin_(children.rbegin()),
         end_(children.rend()) {
   }
-  virtual ~EventTargetIteratorImpl() {}
+  ~EventTargetIteratorImpl() override {}
 
-  virtual EventTarget* GetNextTarget() override {
+  EventTarget* GetNextTarget() override {
     if (begin_ == end_)
       return NULL;
     EventTarget* target = *(begin_);
     ++begin_;
     return target;
   }
 
  private:
   typename std::vector<T*>::const_reverse_iterator begin_;
   typename std::vector<T*>::const_reverse_iterator end_;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_EVENT_TARGET_ITERATOR_H_