virtual/override specifier cleanup in ui/events/ozone/layout/xkb

Found when building with Ozone and use_xkbcommon=1 on Linux.

BUG=417463

Review URL: https://codereview.chromium.org/831373004

Cr-Commit-Position: refs/heads/master@{#310114}

ui/events/ozone/layout/xkb/xkb_evdev_codes.h

@@ -13,8 +13,8 @@ namespace ui {
 class EVENTS_OZONE_LAYOUT_EXPORT XkbEvdevCodes : public XkbKeyCodeConverter {
  public:
   XkbEvdevCodes();
-  virtual ~XkbEvdevCodes();
-  virtual xkb_keycode_t DomCodeToXkbKeyCode(DomCode dom_code) const override;
+  ~XkbEvdevCodes() override;
+  xkb_keycode_t DomCodeToXkbKeyCode(DomCode dom_code) const override;
 };
 
 }  // namespace ui

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h

@@ -21,21 +21,21 @@ class EVENTS_OZONE_LAYOUT_EXPORT XkbKeyboardLayoutEngine
     : public KeyboardLayoutEngine {
  public:
   XkbKeyboardLayoutEngine(const XkbKeyCodeConverter& converter);
-  virtual ~XkbKeyboardLayoutEngine();
+  ~XkbKeyboardLayoutEngine() override;
 
   // KeyboardLayoutEngine:
-  virtual bool CanSetCurrentLayout() const override;
-  virtual bool SetCurrentLayoutByName(const std::string& layout_name) override;
-
-  virtual bool UsesISOLevel5Shift() const override;
-  virtual bool UsesAltGr() const override;
-
-  virtual bool Lookup(DomCode dom_code,
-                      int flags,
-                      DomKey* dom_key,
-                      base::char16* character,
-                      KeyboardCode* key_code,
-                      uint32* platform_keycode) const override;
+  bool CanSetCurrentLayout() const override;
+  bool SetCurrentLayoutByName(const std::string& layout_name) override;
+
+  bool UsesISOLevel5Shift() const override;
+  bool UsesAltGr() const override;
+
+  bool Lookup(DomCode dom_code,
+              int flags,
+              DomKey* dom_key,
+              base::char16* character,
+              KeyboardCode* key_code,
+              uint32* platform_keycode) const override;
 
  protected:
   // Table for EventFlagsToXkbFlags().