Merge "Replace WallpaperData File fields with methods" into udc-qpr-dev am: c18e0fe35c am: b2df98ec78

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23766386

Change-Id: Iff0fdc5fce37272ffba15e4577445a9fb332786c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>