When the "Legends" brand was introduced, the announcement mentioned that "all Star Wars creative development" would be coordinated, and Lucasfilm President Kathleen Kennedy specifically mentioned games:
We’re set to bring Star Wars back to the big screen, and continue the adventure through games, books, comics, and new formats that are just emerging.
Regarding Battlefront (2015) specifically, an employee of the developer (DICE) stated that its canon status is "complicated". Outcomes which contradict canon (e.g. the Empire winning at the Battle of Endor) would obviously be non-canon, but everything else in the game is made to be as canon as possible.
For example, DICE often traveled to the real-world locations where the Original Trilogy was shot (such as California, for Endor), and DICE designed the planet Sullust with Lucasfilm's approval:
Sullust, as seen in Battlefront, is the Lucasfilm-approved version of the planet. Nothing appears in Star Wars anymore without substantial deliberation, and with no proper "Expanded Universe" in Lucasfilm's current lexicon, the Sullust created by DICE is Sullust.
Photogrammetry was used on the original props (such as the Death Star and Darth Vader's helmet) so characters, vehicles, ships, etc. are as realistically dimensioned as possible. DICE was given access to the original sounds from the films, so the sounds are also as true to the films as possible.
It's also worth noting that the canon summary listed in Star Wars: A New Dawn includes Battlefront:
(Technically, this is referring to the novel Battlefront: Twilight Company which was based on the game.)
Perhaps the best way to describe the game's canon status is: everything in the game which doesn't contradict existing canon is itself canon.