Add the native implementation for NetworkStatsService to read the
uidStatsMap and tagStatsMap to get the network traffic information.
Currently the implementation only try to get the data from bpf for a
reference but the final value returned is still from old xt_qtaguid
module. So the result will not be effected. The bpf implementation is
depending on libbpf inside netd.
Bug: 30950746
Test: CtsNetTestCases -t android.net.cts.TrafficStatsTest
Change-Id: Ia85e4d4d602f6bd536739d89085e6dc37ad82e15
Move the native implementation of TrafficStats to NetworkStatsService
and apps need to get the NetworkStatsService binder interface from
system_server in order to get the network usage stats since boot. This
implementation can hide the detail of retrieving network traffic
information from apps and the NetworkStatsService can choose which
methoed it use to get the data depending on the kernel version of the
device.
Bug: 30950746
Test: CtsNetTestCases -t android.net.cts.TrafficStatsTest
Change-Id: I53bbefd19aa0b783b9b4b42ea4d76db3e9ec07a3
