Merge "Prevent exfiltration of system files via avatar picker." into tm-dev am: 5489aa36

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19754655



Change-Id: Ia0cefeb6938b14976f34559f4b1d3e4cda5c029a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>