Update platform classes to use OVERRIDE / FINAL when needed

Source/platform/PODArena.h

 /*
  * 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:
  *
  * 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
@@ skipping 46 matching lines @@
 
     // The Arena's default allocator, which uses fastMalloc and
     // fastFree to allocate chunks of storage.
     class FastMallocAllocator : public Allocator {
     public:
         static PassRefPtr<FastMallocAllocator> create()
         {
             return adoptRef(new FastMallocAllocator);
         }
 
-        virtual void* allocate(size_t size) { return fastMalloc(size); }
-        virtual void free(void* ptr) { fastFree(ptr); }
+        virtual void* allocate(size_t size) OVERRIDE { return fastMalloc(size); }
+        virtual void free(void* ptr) OVERRIDE { fastFree(ptr); }
 
     protected:
         FastMallocAllocator() { }
     };
 
     // Creates a new PODArena configured with a FastMallocAllocator.
     static PassRefPtr<PODArena> create()
     {
         return adoptRef(new PODArena);
     }
@@ skipping 112 matching lines @@
 
     RefPtr<Allocator> m_allocator;
     Chunk* m_current;
     size_t m_currentChunkSize;
     Vector<OwnPtr<Chunk> > m_chunks;
 };
 
 } // namespace WebCore
 
 #endif // PODArena_h