Merge "Fix NPE if draging again while animating" into tm-dev am: a876e7b2 am: d1557103

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18570244



Change-Id: If515f22e9d61134919e4cc258c3ffc1301bb10af
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>