Merge "Improve enter and dismiss transition by using snapshot" into udc-dev...

Merge "Improve enter and dismiss transition by using snapshot" into udc-dev am: 472c42cc am: 7397b8f1 am: c0055c17

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23258461



Change-Id: I36076d98aa04b3fbcf240d6edfbeabb5998476b8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>