minor feature: transparent frameless windows having an opaque background when opened in a maximized state. #30863 (Also in 13, 14, 15).Backported for chromium:1206289. #30822.Backported for chromium:1227228. #30816.Security: Backported for 1231134. #30762 (Also in 11).Security: backported for chromium:1221047. #30818.