Revert onSurfaceRedrawNeeded behavior

The wallpaper bitmap will be unloaded after a few seconds to
free memory, this means that onSurfaceRedrawNeeded would need
to synchronously load an image, which may delay app launches.

Test: manually rotate screen
Change-Id: Ib4987265e5a1dd113b7cd2c8ea7c9d8f8ce5a8f3
Fixes: 110732172