Merge "Nullability check for msg module." am: a1ff2e6159 am: 6f42b5a3ae am: 38333734ae am: e6e3747a42

Original change: https://android-review.googlesource.com/c/platform/bionic/+/2539230

Change-Id: I3cc80cdec27b22748668998fbd4704611ec36bdc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>