Make sure all destructors are called in HeapHashMap and HeapHashSet

Source/heap/Visitor.h

 /*
  * Copyright (C) 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 462 matching lines @@
     {
         if (deque.isEmpty())
             return;
         for (typename Deque::const_iterator it = deque.begin(), end = deque.end(); it != end; ++it)
             TraceTrait<T>::trace(visitor, const_cast<T*>(&(*it)));
     }
 };
 
 template<typename T, typename Traits = WTF::VectorTraits<T> >
 class HeapVectorBacking;
-template<typename Key, typename Value, typename Extractor, typename Traits, typename KeyTraits>
-class HeapHashTableBacking;
+
+template<typename Table>
+class HeapHashTableBacking {
+public:
+    static void finalize(void* pointer);
+};
 
 template<typename T>
 class DefaultTraceTrait<T, false> {
 public:
     static void mark(Visitor* visitor, const T* t)
     {
         // Default mark method of the trait just calls the two-argument mark
         // method on the visitor. The second argument is the static trace method
         // of the trait, which by default calls the instance method
         // trace(Visitor*) on the object.
@@ skipping 126 matching lines @@
 struct GCInfoTrait {
     static const GCInfo* get()
     {
         return GCInfoAtBase<typename GetGarbageCollectedBase<T>::type>::get();
     }
 };
 
 }
 
 #endif