Moving prototype transitions into the header of the transition array.

src/profile-generator.cc

Index: src/profile-generator.cc
diff --git a/src/profile-generator.cc b/src/profile-generator.cc
index ea9300604b2778a9560d00af8ceac6622c1a7aa9..d06b62c239ee16bf5eb5e4db5c2a23b1a2273832 100644
--- a/src/profile-generator.cc
+++ b/src/profile-generator.cc
@@ -2013,16 +2013,6 @@ void V8HeapExplorer::ExtractMapReferences(int entry, Map* map) {
                          "descriptors", map->instance_descriptors(),
                          Map::kInstanceDescriptorsOrBitField3Offset);
   }
-  if (map->unchecked_prototype_transitions()->IsFixedArray()) {
-    TagObject(map->prototype_transitions(), "(prototype transitions)");
-    SetInternalReference(map, entry,
-                         "prototype_transitions", map->prototype_transitions(),
-                         Map::kPrototypeTransitionsOrBackPointerOffset);
-  } else {
-    SetInternalReference(map, entry,
-                         "back_pointer", map->GetBackPointer(),
-                         Map::kPrototypeTransitionsOrBackPointerOffset);
-  }
   SetInternalReference(map, entry,
                        "code_cache", map->code_cache(),
                        Map::kCodeCacheOffset);