Apply FINAL to the RenderObject hierarchy.

Source/core/rendering/RenderMultiColumnSet.h

 /*
  * Copyright (C) 2012 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 23 matching lines @@
 // RenderMultiColumnSet represents a set of columns that all have the same width and height. By combining runs of same-size columns into a single
 // object, we significantly reduce the number of unique RenderObjects required to represent columns.
 //
 // A simple multi-column block will have exactly one RenderMultiColumnSet child. A simple paginated multi-column block will have three
 // RenderMultiColumnSet children: one for the content at the bottom of the first page (whose columns will have a shorter height), one
 // for the 2nd to n-1 pages, and then one last column set that will hold the shorter columns on the final page (that may have to be balanced
 // as well).
 //
 // Column spans result in the creation of new column sets as well, since a spanning region has to be placed in between the column sets that
 // come before and after the span.
-class RenderMultiColumnSet : public RenderRegionSet {
+class RenderMultiColumnSet FINAL : public RenderRegionSet {
 public:
     static RenderMultiColumnSet* createAnonymous(RenderFlowThread*);
 
     virtual bool isRenderMultiColumnSet() const OVERRIDE { return true; }
 
     unsigned computedColumnCount() const { return m_computedColumnCount; }
     LayoutUnit computedColumnWidth() const { return m_computedColumnWidth; }
     LayoutUnit computedColumnHeight() const { return m_computedColumnHeight; }
 
     void setComputedColumnWidthAndCount(LayoutUnit width, unsigned count)
@@ skipping 95 matching lines @@
     return static_cast<const RenderMultiColumnSet*>(object);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toRenderMultiColumnSet(const RenderMultiColumnSet*);
 
 } // namespace WebCore
 
 #endif // RenderMultiColumnSet_h