Merge "WallpaperManager getDrawable & al clarifications" into udc-dev am: 5b1d2b53 am: ecc9c2e6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23027354



Change-Id: Iac5830032a6fbf1cfc3ae5c6bac0903d2a77cbe0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>