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: 8b46fa7d

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



Change-Id: I9ada9240c9dfb83ebd506fb8620cdc796a43dc2d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>