There has never been a community in Macomb County named "Warrenville" nor did the city of Warren annex the village located at Mound and Chicago Roads.
The "Village of Warren" was formed on April 28, 1893. It was a one square mile area from 13 Mile Road to 14 Mile Road and extending one-half mile on either side of Mound Road [
source]. This one-square mile area was jointly governed by both the Warren Township board of trustees and the Warren Village council and its population was always counted as part of Warren Township.
The city of Warren was chartered on Oct. 27, 1956 and its area included all of the former Warren Township, including the former Village of Warren. There was no annexation involved in the formation of the city of Warren.