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

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



Change-Id: I502401b3d4542a5c82d82755bcb5443fc02c36d9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>