Fix wallpaper not updating on initial boot.

Update the wallpaper and redraw it unconditionally when the surface
changes. Previously we were not updating the wallpaper when the
surface changed which meant that it remained at the original surface
dimensions. Also, the indication that it was visible comes in too
late to display it cleanly without jank.

Bug: 7310334 fixed.
Change-Id: Ic2ae95ea0b0704183053da1d7a906818651c62c9