Standardize usage of virtual/override/final specifiers.

ash/virtual_keyboard_controller.h

Index: ash/virtual_keyboard_controller.h
diff --git a/ash/virtual_keyboard_controller.h b/ash/virtual_keyboard_controller.h
index ebbc0fde1858a41f2e32c56d971f967ee831eed1..b2788ccd76ed16ccd6a22b0af4bb80a181b8834e 100644
--- a/ash/virtual_keyboard_controller.h
+++ b/ash/virtual_keyboard_controller.h
@@ -14,11 +14,11 @@ namespace ash {
 class ASH_EXPORT VirtualKeyboardController : public ShellObserver {
  public:
   VirtualKeyboardController();
-  virtual ~VirtualKeyboardController();
+  ~VirtualKeyboardController() override;
 
   // ShellObserver:
-  virtual void OnMaximizeModeStarted() override;
-  virtual void OnMaximizeModeEnded() override;
+  void OnMaximizeModeStarted() override;
+  void OnMaximizeModeEnded() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardController);