Merge "Fix NPE of TopTaskTracker" into tm-qpr-dev am: c523de6dc2

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/21894262

Change-Id: I7b256fd8620c02797c7dc25f0943badc7b5ad437
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>