Standardize usage of virtual/override/final specifiers in ash/.

ash/wm/overview/transparent_activate_window_button.cc

Index: ash/wm/overview/transparent_activate_window_button.cc
diff --git a/ash/wm/overview/transparent_activate_window_button.cc b/ash/wm/overview/transparent_activate_window_button.cc
index 5c6a404f57521155f3e45a4cb4972b12df3c8524..212b57cc1bb2e1d6adbfead1d8f68e3beb2eb5e6 100644
--- a/ash/wm/overview/transparent_activate_window_button.cc
+++ b/ash/wm/overview/transparent_activate_window_button.cc
@@ -35,11 +35,9 @@ class TransparentButton
   TransparentActivateWindowButtonDelegate* delegate() { return delegate_; }
 
   // views::View:
-  virtual void OnGestureEvent(ui::GestureEvent* event) override;
+  void OnGestureEvent(ui::GestureEvent* event) override;
 
-  virtual const char* GetClassName() const override {
-    return kTransparentButtonName;
-  }
+  const char* GetClassName() const override { return kTransparentButtonName; }
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;