Make heap.h usable without objects-inl.h header.

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 3f6b9d64a5137e8c963560e9b7823cf565377b24..4229af7c5ea80ddeb6a96156e70fb017f5fab89b 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -2532,7 +2532,7 @@ class ScavengingVisitor : public StaticVisitorBase {
         return;
       }
 
-      heap->DoScavengeObject(first->map(), slot, first);
+      Heap::ScavengeObjectSlow(slot, first);
       object->set_map_word(MapWord::FromForwardingAddress(*slot));
       return;
     }
@@ -2622,7 +2622,7 @@ void Heap::ScavengeObjectSlow(HeapObject** p, HeapObject* object) {
   MapWord first_word = object->map_word();
   SLOW_DCHECK(!first_word.IsForwardingAddress());
   Map* map = first_word.ToMap();
-  map->GetHeap()->DoScavengeObject(map, p, object);
+  map->GetHeap()->scavenging_visitors_table_.GetVisitor(map)(map, p, object);
 }