Begin collecting xtables iface counters.

Add method to parse new iface_stat_fmt proc stats, or return null
when kernel support is unavailable. Add test and remove older, unused
parsing code. Create new "xt" recorder to persist the new xtables
counters when available.

Add SSID support to NetworkIdentity to fix policy tests.

Bug: 6422414
Change-Id: I77f70e9acb79a559ab626f3af5c4f3599801ed43
diff --git a/services/java/com/android/server/NetworkManagementService.java b/services/java/com/android/server/NetworkManagementService.java
index 09d0698..82a7d51 100644
--- a/services/java/com/android/server/NetworkManagementService.java
+++ b/services/java/com/android/server/NetworkManagementService.java
@@ -942,9 +942,15 @@
     }
 
     @Override
-    public NetworkStats getNetworkStatsSummary() {
+    public NetworkStats getNetworkStatsSummaryDev() {
         mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
-        return mStatsFactory.readNetworkStatsSummary();
+        return mStatsFactory.readNetworkStatsSummaryDev();
+    }
+
+    @Override
+    public NetworkStats getNetworkStatsSummaryXt() {
+        mContext.enforceCallingOrSelfPermission(CONNECTIVITY_INTERNAL, TAG);
+        return mStatsFactory.readNetworkStatsSummaryXt();
     }
 
     @Override