Merge "Make MockVpn more realistic and easier to use." am: e191d8d958 am: b1296e900d am: 82f6a11a45 am: 09a0ad7235

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1501814

Change-Id: I1beca5148b05724042e3c2415015f2ffa3ed2be5