Make some NetworkStats APIs system-current

Move iterator and NetworkStats.Entry getters to system-current
according to API council feedback. This reverts parts of
ag/17117903.

Test: TH
Fix: 225168182
  (cherry-picked from ag/17397294)
Change-Id: Ia7fdf8d31a96a26b0bf1682f462292b051560477
Merged-In: Ia7fdf8d31a96a26b0bf1682f462292b051560477
diff --git a/framework-t/api/system-current.txt b/framework-t/api/system-current.txt
index b8ede59..6460fed 100644
--- a/framework-t/api/system-current.txt
+++ b/framework-t/api/system-current.txt
@@ -71,6 +71,7 @@
     method @NonNull public android.net.NetworkStats add(@NonNull android.net.NetworkStats);
     method @NonNull public android.net.NetworkStats addEntry(@NonNull android.net.NetworkStats.Entry);
     method public int describeContents();
+    method @NonNull public java.util.Iterator<android.net.NetworkStats.Entry> iterator();
     method @NonNull public android.net.NetworkStats subtract(@NonNull android.net.NetworkStats);
     method public void writeToParcel(@NonNull android.os.Parcel, int);
     field @NonNull public static final android.os.Parcelable.Creator<android.net.NetworkStats> CREATOR;
@@ -94,6 +95,17 @@
 
   public static class NetworkStats.Entry {
     ctor public NetworkStats.Entry(@Nullable String, int, int, int, int, int, int, long, long, long, long, long);
+    method public int getDefaultNetwork();
+    method public int getMetered();
+    method public long getOperations();
+    method public int getRoaming();
+    method public long getRxBytes();
+    method public long getRxPackets();
+    method public int getSet();
+    method public int getTag();
+    method public long getTxBytes();
+    method public long getTxPackets();
+    method public int getUid();
   }
 
   public class TrafficStats {