void DefNewGeneration::object_iterate_since_last_GC(ObjectClosure* cl) {

  {- -------------------------------------------
  (1) ContiguousSpace::object_iterate() を呼んで, 
      Eden 領域内のオブジェクトに cl 引数の ObjectClosure を適用するだけ.
      ---------------------------------------- -}

      // $$$ This may be wrong in case of "scavenge failure"?
      eden()->object_iterate(cl);
    }