Fix build.

Switch to using public APIs instead of private ones.

Change-Id: Ia3468d94b3dadeb6a000ce419ee08f7e7ba5dc67
diff --git a/core/java/android/net/Proxy.java b/core/java/android/net/Proxy.java
index 39d4ac1..22c30a5 100644
--- a/core/java/android/net/Proxy.java
+++ b/core/java/android/net/Proxy.java
@@ -16,8 +16,6 @@
 
 package android.net;
 
-import org.apache.harmony.luni.platform.INetworkSystem;
-import org.apache.harmony.luni.platform.Platform;
 import org.apache.http.HttpHost;
 
 import android.content.ContentResolver;
@@ -44,8 +42,6 @@
     static final public String PROXY_CHANGE_ACTION =
         "android.intent.action.PROXY_CHANGE";
 
-    static final private INetworkSystem NETIMPL = Platform.getNetworkSystem();
-
     /**
      * Return the proxy host set by the user.
      * @param ctx A Context used to get the settings for the proxy host.
@@ -169,8 +165,7 @@
                 if (host.equalsIgnoreCase("localhost")) {
                     return true;
                 }
-                if (InetAddress.getByAddress(NETIMPL.ipStringToByteArray(host))
-                        .isLoopbackAddress()) {
+                if (InetAddress.getByName(host).isLoopbackAddress()) {
                     return true;
                 }
             }