Merge "Defines flag for refactoring UserSwitcherActivity." into tm-qpr-dev am: 230a7287

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19749162



Change-Id: I4a10dec456a0784172194605848a4f4ec83b278c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>