Merge "Merge "Update wallpaper offset when changing target from null" into sc-dev am: ccdb3242 am: a1d274c9" into sc-qpr1-dev-plus-aosp am: 89d78c25 am: 6db281ac

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

Change-Id: I32ad8041b332a8ff6d2e74c90dbc179ab8795f9b