Merge "Flatten SplitscreenPipMixedHandler into DefaultMixedHandler" into tm-qpr-dev am: 241856132c am: 8b1d5c9be6

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19906750

Change-Id: I766d24019646bffaebacdf8442e79ab0be059f54
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>