The activity can be positioned in the center or in one of the corners.
From there it shifts its position and tries to find a spot where it
doesn't collide with other activities.
The CL also includes a few fixes necessary to pipe the information about
the initial layout through the system.
Change-Id: I2aaf5b6d20044aafec713b7bd4193b05cfbd16f3
9b1ce52f25