Merge "Remember the stack position, including across configuration changes." into rvc-qpr-dev am: 9020ed08e1 am: 2325a9361e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12254380

Change-Id: If8dd12720681c9d095d534aaee8392fc0a4986ec