Validate package name passed to setApplicationRestrictions. am: 8c2c7b4164 am: 9abccf1549 am: a5d9003562 am: bd45773681

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19754637

Change-Id: If24825ff9158b919714df7be3d404bf52ba80670
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>