Don't deallocate the HashTable backing explicitly when it is managed by GC.

Source/wtf/HashTable.h

Index: Source/wtf/HashTable.h
diff --git a/Source/wtf/HashTable.h b/Source/wtf/HashTable.h
index 1289ad48d6c4be60639102583a9b3161c093c0db..84ed89cceef318cc87bf332a52d9e8540a1a7874 100644
--- a/Source/wtf/HashTable.h
+++ b/Source/wtf/HashTable.h
@@ -280,10 +280,12 @@ namespace WTF {
         HashTable();
         ~HashTable()
         {
-            if (LIKELY(!m_table))
-                return;
-            deallocateTable(m_table, m_tableSize);
-            m_table = 0;
+            if (!Allocator::isGarbageCollected) {

[tkent, 2014/03/05 01:12:40]

nit: We prefer early return.

{
    if (Allocator::isGarbageCollected)
        return;
    if (LIKELY(...))

+                if (LIKELY(!m_table))
+                    return;
+                deallocateTable(m_table, m_tableSize);
+                m_table = 0;
+            }
         }
 
         HashTable(const HashTable&);
@@ -887,13 +889,15 @@ namespace WTF {
     template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits, typename Allocator>
     void HashTable<Key, Value, Extractor, HashFunctions, Traits, KeyTraits, Allocator>::deallocateTable(ValueType* table, unsigned size)
     {
-        if (Traits::needsDestruction) {
-            for (unsigned i = 0; i < size; ++i) {
-                if (!isDeletedBucket(table[i]))
-                    table[i].~ValueType();
+        if (!Allocator::isGarbageCollected) {
+            if (Traits::needsDestruction) {
+                for (unsigned i = 0; i < size; ++i) {
+                    if (!isDeletedBucket(table[i]))
+                        table[i].~ValueType();
+                }
             }
+            Allocator::backingFree(table);
         }
-        Allocator::backingFree(table);
     }
 
     template<typename Key, typename Value, typename Extractor, typename HashFunctions, typename Traits, typename KeyTraits, typename Allocator>