Revert "Cherry-pick the relevant parts of master change"

This reverts commit 5a4844e307.

Reason for revert: multiple build breakages b/137069068

Change-Id: If48bfa2d2cab0877a053743b3ec53820d0c4ed6b

core/java/android/net/NetworkUtils.java

@@ -16,15 +16,10 @@
 
 package android.net;
 
-import static android.system.OsConstants.AF_INET;
-import static android.system.OsConstants.AF_INET6;
-
-import android.annotation.NonNull;
 import android.annotation.UnsupportedAppUsage;
 import android.net.shared.Inet4AddressUtils;
 import android.os.Build;
 import android.system.ErrnoException;
-import android.system.Os;
 import android.util.Log;
 import android.util.Pair;
 
@@ -459,30 +454,4 @@ public class NetworkUtils {
         }
         return routedIPCount;
     }
-
-    private static final int[] ADDRESS_FAMILIES = new int[] {AF_INET, AF_INET6};
-
-    /**
-     * Returns true if the hostname is weakly validated.
-     * @param hostname Name of host to validate.
-     * @return True if it's a valid-ish hostname.
-     *
-     * @hide
-     */
-    public static boolean isWeaklyValidatedHostname(@NonNull String hostname) {
-        // TODO(b/34953048): Use a validation method that permits more accurate,
-        // but still inexpensive, checking of likely valid DNS hostnames.
-        final String weakHostnameRegex = "^[a-zA-Z0-9_.-]+$";
-        if (!hostname.matches(weakHostnameRegex)) {
-            return false;
-        }
-
-        for (int address_family : ADDRESS_FAMILIES) {
-            if (Os.inet_pton(address_family, hostname) != null) {
-                return false;
-            }
-        }
-
-        return true;
-    }
 }