Standardize usage of virtual/override/final specifiers.

ash/accelerators/magnifier_key_scroller_unittest.cc

Index: ash/accelerators/magnifier_key_scroller_unittest.cc
diff --git a/ash/accelerators/magnifier_key_scroller_unittest.cc b/ash/accelerators/magnifier_key_scroller_unittest.cc
index c8670a70dce21f09c5ebe89d295fb62077b4b90c..85553699752dcbd27153bf75b66ee3facaef8e91 100644
--- a/ash/accelerators/magnifier_key_scroller_unittest.cc
+++ b/ash/accelerators/magnifier_key_scroller_unittest.cc
@@ -17,10 +17,10 @@ namespace {
 class KeyEventDelegate : public aura::test::TestWindowDelegate {
  public:
   KeyEventDelegate() {}
-  virtual ~KeyEventDelegate() {}
+  ~KeyEventDelegate() override {}
 
   // ui::EventHandler overrides:
-  virtual void OnKeyEvent(ui::KeyEvent* event) override {
+  void OnKeyEvent(ui::KeyEvent* event) override {
     key_event.reset(new ui::KeyEvent(
         event->type(), event->key_code(), event->flags()));
   }