commit bce7364aafd6be4269f9be5f6acfd59cdb80a243
author Chenbo Feng <fengc@google.com> Thu Apr 11 18:44:45 2019 -0700
committer Lorenzo Colitti <lorenzo@google.com> Tue Apr 23 14:21:05 2019 +0000
tree afdb1cbb5fe1c3529a883b00908e1b46020d28f0
parent be0106abced580a34ea89d0484b2851d0b73065c

Add a lock to protect persistent stats snapshot

Since the network stats could be polled from multiple services at
runtime, it is not thread safe for networkStatsFactory to hold a
persistent stats snapshot without any protection. Use a internal lock to
prevent concurrent modification on mPersistentSnapshot to fix the
problem.

Bug: 124764595
Test: android.app.usage.cts.NetworkUsageStatsTest
      android.net.cts.TrafficStatsTest

Change-Id: I73851336452110afb74d6dd1ca5e50047d5b3d4a
Merged-In: I73851336452110afb74d6dd1ca5e50047d5b3d4a
Merged-In: I22afb46f17697e8b6359d4f593802e0f4b95db8b
(cherry picked from commit 25243b4eb93c234412a35f9e5d9f1649f8964f83)