Merge "Update wallpaper offset when changing target from null" into sc-dev am:...

Merge "Update wallpaper offset when changing target from null" into sc-dev am: ccdb3242 am: a1d274c9 am: 04a301b6 am: 38bb486b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15521640

Change-Id: Ia2725900c87ffa3452f81b07b7c02a0e7e768321