Add Map::weak_cell_cache internal link to heap snapshot.

src/profiler/heap-snapshot-generator.cc

Index: src/profiler/heap-snapshot-generator.cc
diff --git a/src/profiler/heap-snapshot-generator.cc b/src/profiler/heap-snapshot-generator.cc
index f39118ed93a648627b4ddcd2807098a601edfc30..1d25396936dddf0bbcd866e8db9bddea2d8fad8e 100644
--- a/src/profiler/heap-snapshot-generator.cc
+++ b/src/profiler/heap-snapshot-generator.cc
@@ -1320,9 +1320,11 @@ void V8HeapExplorer::ExtractMapReferences(int entry, Map* map) {
   }
   TagObject(map->dependent_code(), "(dependent code)");
   MarkAsWeakContainer(map->dependent_code());
-  SetInternalReference(map, entry,
-                       "dependent_code", map->dependent_code(),
+  SetInternalReference(map, entry, "dependent_code", map->dependent_code(),
                        Map::kDependentCodeOffset);
+  TagObject(map->weak_cell_cache(), "(weak cell)");
+  SetInternalReference(map, entry, "weak_cell_cache", map->weak_cell_cache(),
+                       Map::kWeakCellCacheOffset);
 }