Merge "Define flag for wallpaper preview loading animation (1/3)" into udc-qpr-dev am: 930d4147

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24044246



Change-Id: I538bf15bc8df81de44822d8e019e647d33567bea
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>