Merge "Prevent NPE when dragging last bubble from expanded state" into rvc-dev am: d4952538 am: bfca6d95 am: 51a8a427 am: d8ad57f4

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11832765

Change-Id: I7a9383eb7ee84032791ea4593c46be5c87306970