Merge "New hidden API to support the CTS test case that checks the file...

Merge "New hidden API to support the CTS test case that checks the file contents remains unaltered." into udc-dev am: 0fa26314 am: dcc0acb2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22839500



Change-Id: I66a4f42938a0fc92bb92d6571926b04ffd421ad9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>