Fix virtual/override/final usage in Source/core/layout/.

Source/core/layout/LayoutScrollbar.h

 /*
  * Copyright (C) 2008, 2009 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 24 matching lines @@
 
 class LocalFrame;
 class Node;
 class LayoutBox;
 class LayoutScrollbarPart;
 class ComputedStyle;
 
 class LayoutScrollbar final : public Scrollbar {
 public:
     static PassRefPtrWillBeRawPtr<Scrollbar> createCustomScrollbar(ScrollableArea*, ScrollbarOrientation, Node*, LocalFrame* owningFrame = nullptr);
-    virtual ~LayoutScrollbar();
+    ~LayoutScrollbar() override;
 
     LayoutBox* owningLayoutObject() const;
 
     IntRect buttonRect(ScrollbarPart);
     IntRect trackRect(int startLength, int endLength);
     IntRect trackPieceRectWithMargins(ScrollbarPart, const IntRect&);
 
     int minimumThumbLength();
 
-    virtual bool isOverlayScrollbar() const override { return false; }
+    bool isOverlayScrollbar() const override { return false; }
 
     LayoutScrollbarPart* getPart(ScrollbarPart partType) { return m_parts.get(partType); }
 
-    virtual void invalidateRect(const IntRect&) override;
+    void invalidateRect(const IntRect&) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     LayoutScrollbar(ScrollableArea*, ScrollbarOrientation, Node*, LocalFrame*);
 
 private:
     friend class Scrollbar;
 
-    virtual void setParent(Widget*) override;
-    virtual void setEnabled(bool) override;
+    void setParent(Widget*) override;
+    void setEnabled(bool) override;
 
-    virtual void setHoveredPart(ScrollbarPart) override;
-    virtual void setPressedPart(ScrollbarPart) override;
+    void setHoveredPart(ScrollbarPart) override;
+    void setPressedPart(ScrollbarPart) override;
 
-    virtual void styleChanged() override;
+    void styleChanged() override;
 
-    virtual bool isCustomScrollbar() const override { return true; }
+    bool isCustomScrollbar() const override { return true; }
 
     void updateScrollbarParts(bool destroy = false);
 
     PassRefPtr<ComputedStyle> getScrollbarPseudoStyle(ScrollbarPart, PseudoId);
     void updateScrollbarPart(ScrollbarPart, bool destroy = false);
 
     // This Scrollbar(Widget) may outlive the DOM which created it (during tear down),
     // so we keep a reference to the Node which caused this custom scrollbar creation.
     // This will not create a reference cycle as the Widget tree is owned by our containing
     // FrameView which this Node pointer can in no way keep alive. See webkit bug 80610.
     RefPtrWillBeMember<Node> m_owner;
 
     RawPtrWillBeMember<LocalFrame> m_owningFrame;
 
     HashMap<unsigned, LayoutScrollbarPart*> m_parts;
 };
 
 DEFINE_TYPE_CASTS(LayoutScrollbar, ScrollbarThemeClient, scrollbar, scrollbar->isCustomScrollbar(), scrollbar.isCustomScrollbar());
 
 } // namespace blink
 
 #endif // LayoutScrollbar_h