Merge "Clear touch region on dream overlay container on start." into udc-dev am: d01cc57a am: c04352c9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22345065



Change-Id: I9330c7a7d0501ec45bd8d772ad6e9f1d16d12f8e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>