Merge "Dismiss dream when activities are started while dreaming." into tm-dev am: 964c0704c5

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17988655

Change-Id: I0469d3478c5059f21ad8213793bd7b3e49657c81
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>