Remove static background image from Beam when no hw-acceleration.

The Beam scale down animation on is really jerky on devices where
we can't use hardware acceleration. This seems to be due the fact
that we have a static background over which we scale. Removing it
makes the scaling nice and smooth.

Bug: 5567020
Change-Id: Id04bae45713eaa368d03001e5352271f47d26603
3 files changed