Add InetAddresses class to API

Adds methods needed by app developers to avoid them having to call
non-SDK APIs.

Test: tests added to cts
Bug: 78686891
Change-Id: Ic0eadfdab2b111d5ca4becb753f4fe3557806433
diff --git a/core/java/android/net/InetAddresses.java b/core/java/android/net/InetAddresses.java
new file mode 100644
index 0000000..8e6c69a
--- /dev/null
+++ b/core/java/android/net/InetAddresses.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net;
+
+import libcore.net.InetAddressUtils;
+
+import java.net.InetAddress;
+
+/**
+ * Utility methods for {@link InetAddress} implementations.
+ */
+public class InetAddresses {
+
+    private InetAddresses() {}
+
+    /**
+     * Checks to see if the {@code address} is a numeric address (such as {@code "192.0.2.1"} or
+     * {@code "2001:db8::1:2"}).
+     *
+     * <p>A numeric address is either an IPv4 address containing exactly 4 decimal numbers or an
+     * IPv6 numeric address. IPv4 addresses that consist of either hexadecimal or octal digits or
+     * do not have exactly 4 numbers are not treated as numeric.
+     *
+     * <p>This method will never do a DNS lookup.
+     *
+     * @param address the address to parse.
+     * @return true if the supplied address is numeric, false otherwise.
+     */
+    public static boolean isNumericAddress(String address) {
+        return InetAddressUtils.isNumericAddress(address);
+    }
+
+    /**
+     * Returns an InetAddress corresponding to the given numeric address (such
+     * as {@code "192.168.0.1"} or {@code "2001:4860:800d::68"}).
+     *
+     * <p>See {@link #isNumericAddress(String)} (String)} for a definition as to what constitutes a
+     * numeric address.
+     *
+     * <p>This method will never do a DNS lookup.
+     *
+     * @param address the address to parse, must be numeric.
+     * @return an {@link InetAddress} instance corresponding to the address.
+     * @throws IllegalArgumentException if {@code address} is not a numeric address.
+     */
+    public static InetAddress parseNumericAddress(String address) {
+        return InetAddressUtils.parseNumericAddress(address);
+    }
+}
diff --git a/core/java/android/net/NetworkUtils.java b/core/java/android/net/NetworkUtils.java
index 34e9476..c0aa4a6 100644
--- a/core/java/android/net/NetworkUtils.java
+++ b/core/java/android/net/NetworkUtils.java
@@ -17,6 +17,7 @@
 package android.net;
 
 import android.annotation.UnsupportedAppUsage;
+import android.os.Build;
 import android.os.Parcel;
 import android.util.Log;
 import android.util.Pair;
@@ -294,8 +295,10 @@
      * @param addrString
      * @return the InetAddress
      * @hide
+     * @deprecated Use {@link InetAddresses#parseNumericAddress(String)}, if possible.
      */
-    @UnsupportedAppUsage
+    @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.P)
+    @Deprecated
     public static InetAddress numericToInetAddress(String addrString)
             throws IllegalArgumentException {
         return InetAddress.parseNumericAddress(addrString);