Doing this so we don't break current apps. In the future we should
properly position the activity in the stack (i.e. behind all current
user activity/task) and not change the positioning of stacks.
Bug: 21801163
Bug: 13507605
Bug: 22929608
Change-Id: I979b6288e66f5b2ec2a6f22cb8d416e5c68109bd