Oilpan: remove unused tracking of freelist tails.

Source/platform/heap/Heap.cpp

 /*
  * 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 827 matching lines @@
     entry = new (NotNull, address) FreeListEntry(size);
 #if defined(ADDRESS_SANITIZER)
     // For ASan we don't add the entry to the free lists until the asanDeferMemoryReuseCount
     // reaches zero. However we always add entire pages to ensure that adding a new page will
     // increase the allocation space.
     if (HeapPage<Header>::payloadSize() != size && !entry->shouldAddToFreeList())
         return;
 #endif
     int index = bucketIndexForSize(size);
     entry->link(&m_freeLists[index]);
-    if (!m_lastFreeListEntries[index])
-        m_lastFreeListEntries[index] = entry;
     if (index > m_biggestFreeListIndex)
         m_biggestFreeListIndex = index;
 }
 
 template<typename Header>
 bool ThreadHeap<Header>::expandObject(Header* header, size_t newSize)
 {
     ASSERT(header->payloadSize() < newSize);
     size_t allocationSize = allocationSizeFromSize(newSize);
     ASSERT(allocationSize > header->size());
@@ skipping 653 matching lines @@
 void ThreadHeap<Header>::clearFreeLists()
 {
     m_promptlyFreedCount = 0;
     m_freeList.clear();
 }
 
 template<typename Header>
 void FreeList<Header>::clear()
 {
     m_biggestFreeListIndex = 0;
-    for (size_t i = 0; i < blinkPageSizeLog2; i++) {
+    for (size_t i = 0; i < blinkPageSizeLog2; i++)
         m_freeLists[i] = 0;
-        m_lastFreeListEntries[i] = 0;
-    }
 }
 
 template<typename Header>
 int FreeList<Header>::bucketIndexForSize(size_t size)
 {
     ASSERT(size > 0);
     int index = -1;
     while (size) {
         size >>= 1;
         index++;
@@ skipping 1291 matching lines @@
 bool Heap::s_lastGCWasConservative = false;
 bool Heap::s_inGC = false;
 FreePagePool* Heap::s_freePagePool;
 OrphanedPagePool* Heap::s_orphanedPagePool;
 Heap::RegionTree* Heap::s_regionTree = 0;
 size_t Heap::s_allocatedObjectSize = 0;
 size_t Heap::s_allocatedSpace = 0;
 size_t Heap::s_markedObjectSize = 0;
 
 } // namespace blink