Merge "Add flicker test for quick switching to letterbox app" into udc-qpr-dev am: c8a7e355

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23767544



Change-Id: I1a7763ca41c9ab776bcd8cddff8c6d842c284b96
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>