Merge "UI screenshot diff test for user switcher." into tm-qpr-dev am: 2c912c9e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19886014



Change-Id: I49078df9b656612b514ce1c48ad6c619b0faff7d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>