Oilpan: Remove Heap::s_markingVisitor

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 1045 matching lines @@
         RegionTree* m_left;
         RegionTree* m_right;
     };
 
     // Reset counters that track live and allocated-since-last-GC sizes.
     static void resetHeapCounters();
 
     static int heapIndexForObjectSize(size_t);
     static bool isNormalHeapIndex(int);
 
-    static Visitor* s_markingVisitor;
     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 bool s_lastGCWasConservative;
     static FreePagePool* s_freePagePool;
     static OrphanedPagePool* s_orphanedPagePool;
     static RegionTree* s_regionTree;
@@ skipping 310 matching lines @@
     size_t copySize = previousHeader->payloadSize();
     if (copySize > size)
         copySize = size;
     memcpy(address, previous, copySize);
     return address;
 }
 
 } // namespace blink
 
 #endif // Heap_h