Merge "Enforce that NetworkAgentInfo fields are never null." am: 6231aefd06 am: e4286ddb3d

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1553734

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I56dc3dc6daafa2123f8f1fc40007cd52a4f7a21c