It's a bit of a grey area that they haven't addressed directly. Some of the units and settings are canon (ie. they worked with LFL to get the look of Sullust to what they wanted), but obviously the hero character appearances and the like are not canon. The tie-in book Battlefront Twilight Company is definitely canon.
I do believe Battlefront technically makes the Shadow Trooper canon for those keeping score at home. The Shock Trooper was actually already canon thanks to the Star Wars Commander mobile game. So, thanks LFL/Disney canon team. (As an EU fan, this all feels so arbitrary and unnecessary).