Have VisitorHelper<> handle moving object registration.

third_party/WebKit/Source/platform/heap/HeapTest.cpp

Index: third_party/WebKit/Source/platform/heap/HeapTest.cpp
diff --git a/third_party/WebKit/Source/platform/heap/HeapTest.cpp b/third_party/WebKit/Source/platform/heap/HeapTest.cpp
index ffef74e58e408ebfdf484052bc8c3d6bd92d5332..9969e20de01005536c9790c7545b50e395b641e1 100644
--- a/third_party/WebKit/Source/platform/heap/HeapTest.cpp
+++ b/third_party/WebKit/Source/platform/heap/HeapTest.cpp
@@ -349,12 +349,6 @@ class CountingVisitor : public Visitor {
     return true;
   }
 
-  void registerMovingObjectReference(MovableReference*) override {}
-
-  void registerMovingObjectCallback(MovableReference,
-                                    MovingObjectCallback,
-                                    void*) override {}
-
   size_t count() { return m_count; }
   void reset() { m_count = 0; }