Polish app => recents animation (1/N)

As part of building out a better remote app to overview animation, we
first separate out the logic so that we only do the default layout
animation when coming from a Launcher state (i.e. from home or all
apps) and only then, so coming from an app no longer leads to the tasks
animating.

We do this with a simple flag that indicates that recents will be
using a remote animation.

Bug: 132112131
Test: Go to app, go to recents. No layout animation.
Test: Go to home, go to recents. Layout animation works as normal
Change-Id: I30988d944571fd5317d0c9d13e2a99b167c1291b