There is no use of its focusability, and it causes the view to be
accessibility-focusable, which is not unnecessary, given that
all meaningful actions are done with the task stack.
Bug: 21645706
Change-Id: I6fc29d73d720fec417baeb7ad07cd2cd8690441b
Adding some preliminary controls to mirror the currently exposed api
to create new activity stacks, resize stacks, and to move tasks
between stacks.
Change-Id: I3fb51c248f53a1d4c4eb23ca9fb3a76888def1de