Merge "Add synchronized block when accessing global variables" into main

service-t/src/com/android/server/net/NetworkStatsService.java

@@ -517,11 +517,12 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
                     break;
                 }
                 case MSG_NOTIFY_NETWORK_STATUS: {
+                    synchronized (mStatsLock) {
                         // If no cached states, ignore.
                         if (mLastNetworkStateSnapshots == null) break;
-                    // TODO (b/181642673): Protect mDefaultNetworks from concurrent accessing.
                         handleNotifyNetworkStatus(
                                 mDefaultNetworks, mLastNetworkStateSnapshots, mActiveIface);
+                    }
                     break;
                 }
                 case MSG_PERFORM_POLL_REGISTER_ALERT: {