Merge "Merge "Fix NPE in *GenerateChallengeClient" into sc-dev am: 4eaca4eb am: a3913a2c" into sc-v2-dev-plus-aosp am: a6d9df22

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15130759

Change-Id: I9da97b72ed446f25af68c524607b730d9a33e0c7