Merge "Do not letterbox the activity in PiP mode" into udc-dev am: 41667fa9 am: 3b341fdb

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23503609



Change-Id: I2353256a3898fcd653e4b8e1767cf14d72c47780
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>