Revert "Revert "Unhide IpPrefix(InetAddress, int)""

This reverts commit 758ead6dd362f8b7c665603fb9d85038b3f72f27.

Reason for revert: Re-landing changes not related to postsubmit failure

Change-Id: I2f705549d85af4ba45dc294e0a86d757490b1cd7
diff --git a/framework/api/current.txt b/framework/api/current.txt
index c53f29a..a755234 100644
--- a/framework/api/current.txt
+++ b/framework/api/current.txt
@@ -206,6 +206,7 @@
   }
 
   public final class IpPrefix implements android.os.Parcelable {
+    ctor public IpPrefix(@NonNull java.net.InetAddress, @IntRange(from=0, to=128) int);
     method public boolean contains(@NonNull java.net.InetAddress);
     method public int describeContents();
     method @NonNull public java.net.InetAddress getAddress();