Merge "PiP: Disable enter-split button when not visible." into sc-v2-dev am: 229448b89e am: 70a599b11b

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16415929

Change-Id: I0a7f38826af456bf97032b72a5162b64c45190b0