Network stats flag to force complete poll.

Devices currently delay collecting UID stats during common operations
like global alerts to reduce parsing load.  Here we introduce a flag
to always collect UID and iface stats together to aid debugging.

Bug: 5321340
Change-Id: Ia8e1daf1a6f9d5f5cf1f64a04b6b6766ee965ab6

services/tests/servicestests/src/com/android/server/NetworkStatsServiceTest.java

@@ -758,6 +758,7 @@ public class NetworkStatsServiceTest extends AndroidTestCase {
         expect(mSettings.getUidMaxHistory()).andReturn(maxHistory).anyTimes();
         expect(mSettings.getTagMaxHistory()).andReturn(maxHistory).anyTimes();
         expect(mSettings.getTimeCacheMaxAge()).andReturn(DAY_IN_MILLIS).anyTimes();
+        expect(mSettings.getForceCompletePoll()).andReturn(false).anyTimes();
     }
 
     private void expectCurrentTime() throws Exception {