API to adjust network stats. DO NOT MERGE.

Enables system apps to correctly account network usage performed on
behalf of another application.

Bug: 6695246
Change-Id: I39e243afd57936b6b30157a6ca511a17b6c55c39

services/java/com/android/server/net/NetworkStatsService.java

@@ -695,6 +695,14 @@ public class NetworkStatsService extends INetworkStatsService.Stub {
         mGlobalAlertBytes = mSettings.getGlobalAlertBytes(mPersistThreshold);
     }
 
+    @Override
+    public void adjustNetworkStats(int uid, int tag, long rxBytes, long rxPackets, long txBytes,
+            long txPackets, long operationCount) {
+        mContext.enforceCallingOrSelfPermission(MODIFY_NETWORK_ACCOUNTING, TAG);
+
+        // TODO: store adjusted network stats in separate data structure
+    }
+
     /**
      * Receiver that watches for {@link IConnectivityManager} to claim network
      * interfaces. Used to associate {@link TelephonyManager#getSubscriberId()}