Simplify visitor marking mode tracking.

third_party/WebKit/Source/platform/heap/HeapTest.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 300 matching lines @@
       m_count++;                                                   \
   }                                                                \
   bool isMarked(const Type*) override { return false; }            \
   bool ensureMarked(const Type* objectPointer) override {          \
     return ensureMarked(objectPointer);                            \
   }
 
 class CountingVisitor : public Visitor {
  public:
   explicit CountingVisitor(ThreadState* state)
-      : Visitor(state, Visitor::ThreadLocalMarking),
+      : Visitor(state, VisitorMarkingMode::ThreadLocalMarking),
         m_scope(&state->heap().stackFrameDepth()),
         m_count(0) {}
 
   void mark(const void* object, TraceCallback) override {
     if (object)
       m_count++;
   }
 
   void markHeader(HeapObjectHeader* header, TraceCallback callback) override {
     ASSERT(header->payload());
@@ skipping 6235 matching lines @@
       "HeapVector");
   static_assert(
       WTF::IsGarbageCollectedType<HeapDeque<Member<IntWrapper>>>::value,
       "HeapDeque");
   static_assert(WTF::IsGarbageCollectedType<
                     HeapTerminatedArray<Member<IntWrapper>>>::value,
                 "HeapTerminatedArray");
 }
 
 }  // namespace blink