1. getNetworkTotalBytes was used for querying overall statistics
that regards of the NetworkPolicy to calculate the remaining
data warning/limit quota that needs to be send to the lower layer.
2. getNetworkUidBytes was used for querying overall statistics of
apps to find out the rapid traffic that caused by an abnormal
app behavior.
This change replaces getNetwork[Total|Uid]Bytes with APIs that are
about to expose, and introduces a dependencies object for better
unit test injection.
Test: atest NetworkPolicyManagerServiceTest
Bug: 204830222
Change-Id: I802d2316fb22886e951456df0941c09176c981f8
5e3545fc7f