The bars are supposed to sit on top of the window so
that if they are transparent (which is the default case
for the action bar), the window background shows through.
Fix this using a layout to represent the window content
(all but the system bar) in which the title/action bars
and the layout content sits. This layout receives the
windowBackground drawable.
Change-Id: I8072c5ff52f585fa32acb589d8526e1c13cbcd94
abc33e014d