Merge "Use public API of NetworkAgent in TestNetworkService" am: 0903bf5de7 am: 374ccf4359 am: 0d27afe2c3

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1505291

Change-Id: I95d8e2269bf3acf3161630539c9a5c632e77d3e4