I had a possibly similar stone chip last week in mine, looked slightly different, less damage at the edges (mine was about 4.5mm across). For mine, Autoglass came out and said unless it had actually cracked the top layer, anything they do will just come off in weeks/months as without a crack to fill, its just a surface patch. The guy described how to look at the reflections to tell if it had cracked. The option was leave it and call them again if a crack appeared or to get the windscreen replaced. I went for the first option.