Previews in the wallpaper picker are offset to match the homescreen parallax.

When "Wallpapers" is selected from the overlay, the current wallpaper parallax
offset is sent to the WallpaperPickerActivity as an Intent extra. The CropView
then uses that offset when previewing new wallpapers to ensure the preview looks
exactly the same as the actual wallpaper will when set.

Note that this fix doesn't seem to work for DefaultWallpaperInfo - that will
come in a future CL.

Bug: 23568800
Change-Id: I41c5bbbfdabfeb4e20d77e9b5804842a03211edf