Update more core classes to use OVERRIDE / FINAL when needed

Source/core/rendering/CompositedLayerMapping.h

 /*
  * Copyright (C) 2009, 2010, 2011 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 59 matching lines @@
 // GraphicsLayers of the composited layer tree. Each instance of CompositedLayerMapping
 // manages a small cluster of GraphicsLayers and the references to which RenderLayers
 // and paint phases contribute to each GraphicsLayer.
 //
 // Currently (Oct. 2013) there is one CompositedLayerMapping for each RenderLayer,
 // but this is likely to evolve soon.
 class CompositedLayerMapping FINAL : public GraphicsLayerClient {
     WTF_MAKE_NONCOPYABLE(CompositedLayerMapping); WTF_MAKE_FAST_ALLOCATED;
 public:
     explicit CompositedLayerMapping(RenderLayer*);
-    ~CompositedLayerMapping();
+    virtual ~CompositedLayerMapping();
 
     RenderLayer* owningLayer() const { return m_owningLayer; }
 
     enum UpdateAfterLayoutFlag {
         CompositingChildrenOnly = 1 << 0,
         NeedsFullRepaint = 1 << 1,
         IsUpdateRoot = 1 << 2
     };
     typedef unsigned UpdateAfterLayoutFlags;
     void updateAfterLayout(UpdateAfterLayoutFlags);
@@ skipping 261 matching lines @@
     bool m_isMainFrameRenderViewLayer;
     bool m_requiresOwnBackingStoreForIntrinsicReasons;
     bool m_requiresOwnBackingStoreForAncestorReasons;
     bool m_canCompositeFilters;
     bool m_backgroundLayerPaintsFixedRootBackground;
 };
 
 } // namespace WebCore
 
 #endif // CompositedLayerMapping_h