Update fetch / loader classes to use OVERRIDE / FINAL when needed

Source/core/fetch/MemoryCache.h

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller <mueller@kde.org>
     Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
@@ skipping 41 matching lines @@
 //        |-----|                              Dead: -
 //        |----------|                         Live: +
 //      --|----------|                         Cache boundary: | (objects outside this mark have been evicted)
 //      --|----------++++++++++|
 // -------|-----+++++++++++++++|
 // -------|-----+++++++++++++++|+++++
 
 // Enable this macro to periodically log information about the memory cache.
 #undef MEMORY_CACHE_STATS
 
-class MemoryCache : public blink::WebThread::TaskObserver {
+class MemoryCache FINAL : public blink::WebThread::TaskObserver {
     WTF_MAKE_NONCOPYABLE(MemoryCache); WTF_MAKE_FAST_ALLOCATED;
 public:
     MemoryCache();
     virtual ~MemoryCache();
 
     typedef HashMap<String, Resource*> ResourceMap;
 
     struct LRUList {
         Resource* m_head;
         Resource* m_tail;
@@ skipping 140 matching lines @@
 
 // Returns the global cache.
 MemoryCache* memoryCache();
 
 // Sets the global cache, used to swap in a test instance.
 void setMemoryCacheForTesting(MemoryCache*);
 
 }
 
 #endif