Let network requests see VPNs.

Test: runtest frameworks-net
Test: also tested with VPN app
Test: also cts passing
Change-Id: I3b16caad7787c3c1f2921ca1583815c89efbadc5

core/java/android/net/NetworkCapabilities.java

@@ -894,6 +894,17 @@ public final class NetworkCapabilities implements Parcelable {
      */
     private Set<UidRange> mUids = null;
 
+    /**
+     * Convenience method to set the UIDs this network applies to to a single UID.
+     * @hide
+     */
+    public NetworkCapabilities setSingleUid(int uid) {
+        final ArraySet<UidRange> identity = new ArraySet<>(1);
+        identity.add(new UidRange(uid, uid));
+        setUids(identity);
+        return this;
+    }
+
     /**
      * Set the list of UIDs this network applies to.
      * This makes a copy of the set so that callers can't modify it after the call.