Fix errorprone warnings that should be errors am: 083e4f4123 am: d76e8fd2e9

Original change: https://android-review.googlesource.com/c/platform/external/mobile-data-download/+/2256435

Change-Id: I4a265e51793be4236d28e25a6310e5456f592622
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>