Devirtualize Visitor and remove inline visitor specialization.

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 417 matching lines @@
   void processMarkingStack(Visitor*);
   void postMarkingProcessing(Visitor*);
   void globalWeakProcessing(Visitor*);
 
   void preGC();
   void postGC(BlinkGC::GCType);
 
   // Conservatively checks whether an address is a pointer in any of the
   // thread heaps.  If so marks the object pointed to as live.
   Address checkAndMarkPointer(Visitor*, Address);
+#if DCHECK_IS_ON()
+  Address checkAndMarkPointer(Visitor*,
+                              Address,
+                              MarkedPointerCallbackForTesting);
+#endif
 
   size_t objectPayloadSizeForTesting();
 
   void flushHeapDoesNotContainCache();
 
   FreePagePool* getFreePagePool() { return m_freePagePool.get(); }
   OrphanedPagePool* getOrphanedPagePool() { return m_orphanedPagePool.get(); }
 
   // This look-up uses the region search tree and a negative contains cache to
   // provide an efficient mapping from arbitrary addresses to the containing
@@ skipping 237 matching lines @@
     address = ThreadHeap::allocateOnArenaIndex(state, size, arenaIndex,
                                                gcInfoIndex, typeName);
   }
   size_t copySize = previousHeader->payloadSize();
   if (copySize > size)
     copySize = size;
   memcpy(address, previous, copySize);
   return address;
 }
 
-template <typename Derived>
 template <typename T>
-void VisitorHelper<Derived>::handleWeakCell(Visitor* self, void* object) {
+void Visitor::handleWeakCell(Visitor* self, void* object) {
   T** cell = reinterpret_cast<T**>(object);
   if (*cell && !ObjectAliveTrait<T>::isHeapObjectAlive(*cell))
     *cell = nullptr;
 }
 
 }  // namespace blink
 
+#include "platform/heap/VisitorImpl.h"
+
 #endif  // Heap_h