This is a space where the grounds of Kao Corporation's Tokyo factory are open for use as a rest area. There are seven or eight large stone benches. It's shady in the afternoon, so it can be cold, but it might be comfortable depending on the season. Since there's hardly anyone there, you can stay for a while.
It's a 20-minute walk from JR Kameido Station, or you can take a bus bound for Nippori Station and get off right in front of Tachibana 1-chome bus stop.