Refactor Maps' code_cache

src/heap/object-stats.cc

Index: src/heap/object-stats.cc
diff --git a/src/heap/object-stats.cc b/src/heap/object-stats.cc
index 0198c6bacf8075dc1721282781eba6e1dae61077..0c34872fb4dffcad9fcfb80397ab526873321bd2 100644
--- a/src/heap/object-stats.cc
+++ b/src/heap/object-stats.cc
@@ -187,7 +187,7 @@ void ObjectStatsVisitor::Visit<ObjectStatsVisitor::kVisitMap>(Map* map,
                                                       fixed_array_size);
   }
   if (map_obj->has_code_cache()) {
-    FixedArray* cache = FixedArray::cast(map_obj->code_cache());
+    FixedArray* cache = map_obj->code_cache();
     heap->object_stats_->RecordFixedArraySubTypeStats(MAP_CODE_CACHE_SUB_TYPE,
                                                       cache->Size());
   }