Merge "Add feature flag for advanced vpn" into tm-qpr-dev am: e8a0ffc8 am: 4e622a83

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21957563



Change-Id: I5384f8adaa8af12083eb3d4e551a8c863213b5fd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>