Merge "[wm] fix npe when removing trusted task overlays" into udc-qpr-dev am: b6a07bea

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23481001



Change-Id: I4c1b1e0307312c73bbde446ff3b60d8cbb98cfa7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>