Merge "Prevent flickering between fullscreen and multi-window of main stage"...

Merge "Prevent flickering between fullscreen and multi-window of main stage" into sc-v2-dev am: 5917a9cc am: 244aff46

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15216393

Change-Id: If701726f5357fcf070db1cdc5aa44cd4fdaccb69