Standardize usage of virtual/override/final specifiers.

ash/ime/candidate_view.h

Index: ash/ime/candidate_view.h
diff --git a/ash/ime/candidate_view.h b/ash/ime/candidate_view.h
index f800a40a5dd1c0188d27de6ee5a065d0a0109362..6b1c650ec64ba2b4225148a5920e604fb66e5521 100644
--- a/ash/ime/candidate_view.h
+++ b/ash/ime/candidate_view.h
@@ -20,7 +20,7 @@ class ASH_EXPORT CandidateView : public views::CustomButton {
  public:
   CandidateView(views::ButtonListener* listener,
                 ui::CandidateWindow::Orientation orientation);
-  virtual ~CandidateView() {}
+  ~CandidateView() override {}
 
   void GetPreferredWidths(int* shortcut_width,
                           int* candidate_width);
@@ -40,12 +40,12 @@ class ASH_EXPORT CandidateView : public views::CustomButton {
   FRIEND_TEST_ALL_PREFIXES(CandidateWindowViewTest, ShortcutSettingTest);
 
   // Overridden from views::CustomButton:
-  virtual void StateChanged() override;
+  void StateChanged() override;
 
   // Overridden from View:
-  virtual bool OnMouseDragged(const ui::MouseEvent& event) override;
-  virtual void Layout() override;
-  virtual gfx::Size GetPreferredSize() const override;
+  bool OnMouseDragged(const ui::MouseEvent& event) override;
+  void Layout() override;
+  gfx::Size GetPreferredSize() const override;
 
   // The orientation of the candidate view.
   ui::CandidateWindow::Orientation orientation_;