Use larger crop surface size to allow for parallax scrolling

In ImagePreviewFragment, we were always limiting the width of the wallpaper
to match the hostViewSize, so the wallpaper ended up cropped to one screen
size.
The current solution still forces one screen size for wallpapers whose
size actually matches the screen, but we need a better longer term solution

Fixes: 160111671
Change-Id: Ic5e6547569eb40ca3a7799bf5519ca32dcedc169
3 files changed