Smaller vtbls in RenderObject

Source/core/rendering/RenderFullScreen.cpp

Index: Source/core/rendering/RenderFullScreen.cpp
diff --git a/Source/core/rendering/RenderFullScreen.cpp b/Source/core/rendering/RenderFullScreen.cpp
index 27f4fa2954a71dcfd2376bfd11b847a63874aa55..48bf58459fd73996499f80696d8e631d5c6fd658 100644
--- a/Source/core/rendering/RenderFullScreen.cpp
+++ b/Source/core/rendering/RenderFullScreen.cpp
@@ -45,7 +45,7 @@ public:
         setDocumentForAnonymous(&owner->document());
     }
 private:
-    virtual bool isRenderFullScreenPlaceholder() const override { return true; }
+    virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectRenderFullScreenPlaceholder || RenderBlockFlow::isOfType(type); }
     virtual void willBeDestroyed() override;
     RenderFullScreen* m_owner;
 };