Standardize usage of virtual/override/final specifiers.

ash/accelerators/spoken_feedback_toggler.h

Index: ash/accelerators/spoken_feedback_toggler.h
diff --git a/ash/accelerators/spoken_feedback_toggler.h b/ash/accelerators/spoken_feedback_toggler.h
index 067a7d1ec547510a596889fd46d8b217956a02f5..51bf9851632af4a917cc52d384f6ba5a36b4c0b9 100644
--- a/ash/accelerators/spoken_feedback_toggler.h
+++ b/ash/accelerators/spoken_feedback_toggler.h
@@ -39,13 +39,13 @@ class ASH_EXPORT SpokenFeedbackToggler : public KeyHoldDetector::Delegate {
 
  private:
   // KeyHoldDetector overrides:
-  virtual bool ShouldProcessEvent(const ui::KeyEvent* event) const override;
-  virtual bool IsStartEvent(const ui::KeyEvent* event) const override;
-  virtual void OnKeyHold(const ui::KeyEvent* event) override;
-  virtual void OnKeyUnhold(const ui::KeyEvent* event) override;
+  bool ShouldProcessEvent(const ui::KeyEvent* event) const override;
+  bool IsStartEvent(const ui::KeyEvent* event) const override;
+  void OnKeyHold(const ui::KeyEvent* event) override;
+  void OnKeyUnhold(const ui::KeyEvent* event) override;
 
   SpokenFeedbackToggler();
-  virtual ~SpokenFeedbackToggler();
+  ~SpokenFeedbackToggler() override;
 
   bool toggled_;