Merge "Tv PiP: add constant for custom actions extra." into udc-dev am: 1573f2da am: 40568f21

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22673944



Change-Id: Ica44d4a622de4c1719504effdb0c4cc608e5e154
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>