Standardize usage of virtual/override/final in ui/

ui/gfx/display_change_notifier_unittest.cc

Index: ui/gfx/display_change_notifier_unittest.cc
diff --git a/ui/gfx/display_change_notifier_unittest.cc b/ui/gfx/display_change_notifier_unittest.cc
index 700793a051e40b234244246b7e63456118292a4d..47b5bd064b64c2c3ff574af9fd751d9dd4459925 100644
--- a/ui/gfx/display_change_notifier_unittest.cc
+++ b/ui/gfx/display_change_notifier_unittest.cc
@@ -19,18 +19,14 @@ class MockDisplayObserver : public DisplayObserver {
       latest_metrics_change_(DisplayObserver::DISPLAY_METRIC_NONE)
   {}
 
-  virtual ~MockDisplayObserver() { }
+  ~MockDisplayObserver() override {}
 
-  virtual void OnDisplayAdded(const Display& display) override {
-    display_added_++;
-  }
+  void OnDisplayAdded(const Display& display) override { display_added_++; }
 
-  virtual void OnDisplayRemoved(const Display& display) override {
-    display_removed_++;
-  }
+  void OnDisplayRemoved(const Display& display) override { display_removed_++; }
 
-  virtual void OnDisplayMetricsChanged(const Display& display,
-                                       uint32_t metrics) override {
+  void OnDisplayMetricsChanged(const Display& display,
+                               uint32_t metrics) override {
     display_changed_++;
     latest_metrics_change_ = metrics;
   }