Oilpan: Introduce memory pool for CallbackStacks

third_party/WebKit/Source/platform/heap/Heap.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 378 matching lines @@
     static void reportMemoryUsageHistogram();
     static void reportMemoryUsageForTracing();
 
 private:
     // Reset counters that track live and allocated-since-last-GC sizes.
     void resetHeapCounters();
 
     static int arenaIndexForObjectSize(size_t);
     static bool isNormalArenaIndex(int);
 
+    void commitCallbackStacks();
     void decommitCallbackStacks();
 
     RecursiveMutex m_threadAttachMutex;
     ThreadStateSet m_threads;
     ThreadHeapStats m_stats;
     std::unique_ptr<RegionTree> m_regionTree;
     std::unique_ptr<HeapDoesNotContainCache> m_heapDoesNotContainCache;
     std::unique_ptr<SafePointBarrier> m_safePointBarrier;
     std::unique_ptr<FreePagePool> m_freePagePool;
     std::unique_ptr<OrphanedPagePool> m_orphanedPagePool;
@@ skipping 210 matching lines @@
 void VisitorHelper<Derived>::handleWeakCell(Visitor* self, void* object)
 {
     T** cell = reinterpret_cast<T**>(object);
     if (*cell && !ObjectAliveTrait<T>::isHeapObjectAlive(*cell))
         *cell = nullptr;
 }
 
 } // namespace blink
 
 #endif // Heap_h