Standardize usage of virtual/override/final specifiers.

ui/views/test/test_widget_observer.h

Index: ui/views/test/test_widget_observer.h
diff --git a/ui/views/test/test_widget_observer.h b/ui/views/test/test_widget_observer.h
index 064db84e01c80c3246d913bc94b5eea0ed502e69..fc3e8ecd66085a792e374b1dc2c9bb9b9a426f83 100644
--- a/ui/views/test/test_widget_observer.h
+++ b/ui/views/test/test_widget_observer.h
@@ -18,13 +18,13 @@ namespace test {
 class TestWidgetObserver : public WidgetObserver {
  public:
   explicit TestWidgetObserver(Widget* widget);
-  virtual ~TestWidgetObserver();
+  ~TestWidgetObserver() override;
 
   bool widget_closed() const { return widget_ == NULL; }
 
  private:
   // WidgetObserver overrides:
-  virtual void OnWidgetDestroying(Widget* widget) override;
+  void OnWidgetDestroying(Widget* widget) override;
 
   Widget* widget_;