Smaller vtbls in RenderObject

Source/core/rendering/RenderSliderThumb.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 27 matching lines @@
 namespace blink {
 
 class SliderThumbElement;
 
 class RenderSliderThumb final : public RenderBlockFlow {
 public:
     RenderSliderThumb(SliderThumbElement*);
     void updateAppearance(RenderStyle* parentStyle);
 
 private:
-    virtual bool isSliderThumb() const override;
+    virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectSliderThumb || RenderBlockFlow::isOfType(type); }
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSliderThumb, isSliderThumb());
 
 } // namespace blink
 
 #endif // RenderSliderThumb_h