Merge "Replace BaseNetworkObserver with BaseNetdUnsolicitedEventListener" am: 692b07f7dd am: 076ce5f262

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1547454

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I4039814ea4c48bdaf7e54dbf3d1242a18235ee7b