Merge "Prevent exfiltration of system files via avatar picker." into tm-dev am: 5489aa365f am: addd691c0b am: 46dd72d5f8

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

Change-Id: I27eeeba06ab322e48b2cef1144e5682c363a3188
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>