Merge "Choose opaque activity for fixed rotation with entering pip" into...

Merge "Choose opaque activity for fixed rotation with entering pip" into sc-v2-dev am: fd566b80 am: 4209eaa2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16221430

Change-Id: I2ac0aba6ed4834707ee906113a6a6871a54a7d10