Update more core classes to use OVERRIDE / FINAL when needed

Source/core/rendering/RenderFlowThread.h

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 76 matching lines @@
     bool hasRegionsWithStyling() const { return m_hasRegionsWithStyling; }
     void checkRegionsWithStyling();
     virtual void regionChangedWritingMode(RenderRegion*) { }
 
     void validateRegions();
     void invalidateRegions();
     bool hasValidRegionInfo() const { return !m_regionsInvalidated && !m_regionList.isEmpty(); }
 
     static PassRefPtr<RenderStyle> createFlowThreadStyle(RenderStyle* parentStyle);
 
-    void styleDidChange(StyleDifference, const RenderStyle* oldStyle);
+    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
 
     void repaintRectangleInRegions(const LayoutRect&) const;
 
     LayoutPoint adjustedPositionRelativeToOffsetParent(const RenderBoxModelObject&, const LayoutPoint&);
 
     LayoutUnit pageLogicalTopForOffset(LayoutUnit);
     LayoutUnit pageLogicalWidthForOffset(LayoutUnit);
     LayoutUnit pageLogicalHeightForOffset(LayoutUnit);
     LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit, PageBoundaryRule = IncludePageBoundary);
 
@@ skipping 206 matching lines @@
 };
 
 template <> struct ValueToString<RenderRegion*> {
     static String string(const RenderRegion* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace WebCore
 
 #endif // RenderFlowThread_h