Revert of Oilpan: Decommit backing storage of 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 261 matching lines @@
     static uint16_t gcGeneration() { return s_gcGeneration; }
 #endif
 
 private:
     // Reset counters that track live and allocated-since-last-GC sizes.
     static void resetHeapCounters();
 
     static int heapIndexForObjectSize(size_t);
     static bool isNormalHeapIndex(int);
 
-    static void decommitCallbackStacks();
-
     static CallbackStack* s_markingStack;
     static CallbackStack* s_postMarkingCallbackStack;
     static CallbackStack* s_globalWeakCallbackStack;
     static CallbackStack* s_ephemeronStack;
     static HeapDoesNotContainCache* s_heapDoesNotContainCache;
     static bool s_shutdownCalled;
     static FreePagePool* s_freePagePool;
     static OrphanedPagePool* s_orphanedPagePool;
     static RegionTree* s_regionTree;
     static size_t s_allocatedSpace;
@@ skipping 204 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