Oilpan:Allow custom handling of classes that contain weak pointers that are embedded in collections.

Source/wtf/HashTable.h

 /*
  * Copyright (C) 2005, 2006, 2007, 2008, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008 David Levin <levin@chromium.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 1102 matching lines @@
             HashTableType* table = reinterpret_cast<HashTableType*>(closure);
             if (table->m_table) {
                 // This just marks it live and does not push anything onto the
                 // marking stack.
                 Allocator::markNoTracing(visitor, table->m_table);
                 // Now perform weak processing (this is a no-op if the backing
                 // was accessible through an iterator and was already marked
                 // strongly).
                 for (typename HashTableType::ValueType* element = table->m_table + table->m_tableSize - 1; element >= table->m_table; element--) {
                     if (!HashTableType::isEmptyOrDeletedBucket(*element)) {
-                        if (Allocator::hasDeadMember(visitor, *element)) {
+                        if (Traits::shouldRemoveFromCollection(visitor, *element)) {
                             table->registerModification();
                             HashTableType::deleteBucket(*element); // Also calls the destructor.
                             table->m_deletedCount++;
                             table->m_keyCount--;
                             // We don't rehash the backing until the next add
                             // or delete, because that would cause allocation
                             // during GC.
                         }
                     }
                 }
@@ skipping 133 matching lines @@
         CollectionIterator end(toBeRemoved.end());
         for (CollectionIterator it(toBeRemoved.begin()); it != end; ++it)
             collection.remove(*it);
     }
 
 } // namespace WTF
 
 #include "wtf/HashIterators.h"
 
 #endif // WTF_HashTable_h