The city’s historic district commission has approved plans for the renovation of the building on Islington Street into the White Heron Tea and Coffee, a cafe with a tea-packaging component. A surf shop and a martial arts studio are already on the property. Last month the board of adjustment approved a change of use of the building at 601 Islington St. from retail to restaurant and light industry and granted a variance to allow 20 parking spaces where 60 spaces are required.