Annotate @SystemApi on some WifiManager methods.

Bug: 17112931
Change-Id: I5980bc46bc1f16316caecd7fcc6cd771b8ca6cdf
diff --git a/wifi/java/android/net/wifi/WifiManager.java b/wifi/java/android/net/wifi/WifiManager.java
index e27bd7e..3d976e7 100644
--- a/wifi/java/android/net/wifi/WifiManager.java
+++ b/wifi/java/android/net/wifi/WifiManager.java
@@ -1696,6 +1696,7 @@
      *
      * @hide
      */
+    @SystemApi
     public void connect(WifiConfiguration config, ActionListener listener) {
         if (config == null) throw new IllegalArgumentException("config cannot be null");
         validateChannel();
@@ -1718,6 +1719,7 @@
      * initialized again
      * @hide
      */
+    @SystemApi
     public void connect(int networkId, ActionListener listener) {
         if (networkId < 0) throw new IllegalArgumentException("Network id cannot be negative");
         validateChannel();
@@ -1742,6 +1744,7 @@
      * initialized again
      * @hide
      */
+    @SystemApi
     public void save(WifiConfiguration config, ActionListener listener) {
         if (config == null) throw new IllegalArgumentException("config cannot be null");
         validateChannel();
@@ -1761,6 +1764,7 @@
      * initialized again
      * @hide
      */
+    @SystemApi
     public void forget(int netId, ActionListener listener) {
         if (netId < 0) throw new IllegalArgumentException("Network id cannot be negative");
         validateChannel();
@@ -1776,6 +1780,7 @@
      * initialized again
      * @hide
      */
+    @SystemApi
     public void disable(int netId, ActionListener listener) {
         if (netId < 0) throw new IllegalArgumentException("Network id cannot be negative");
         validateChannel();