Merge "Have NetworkPolicyManagerService create MultipathPolicyTracker" am: 99f0ad7b3e

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1519960

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Idc48a3618c12f332a5e067973519ab7777058fdf