WifiManager: add new methods to start softap

Add two new methods to start/stop softap in WifiService.  These are
internal calls that allow WifiService and ConnectivityService to
coordinate the switch to and from softap mode.  These calls will not be
callable by apps and are protected by the NETWORK_STACK permission.  The
calls are added in this CL, but are not used at this time.

Bug: 36540346
Test: compiles

Change-Id: Idabdba7f779cbac999ff88d8993b2f4b1f4a1624

wifi/java/android/net/wifi/IWifiManager.aidl

@@ -125,6 +125,10 @@ interface IWifiManager
 
     void setWifiApEnabled(in WifiConfiguration wifiConfig, boolean enable);
 
+    boolean startSoftAp(in WifiConfiguration wifiConfig);
+
+    boolean stopSoftAp();
+
     int getWifiApEnabledState();
 
     WifiConfiguration getWifiApConfiguration();

wifi/java/android/net/wifi/WifiManager.java

@@ -16,6 +16,7 @@
 
 package android.net.wifi;
 
+import android.annotation.Nullable;
 import android.annotation.SdkConstant;
 import android.annotation.SdkConstant.SdkConstantType;
 import android.annotation.SystemApi;
@@ -1716,6 +1717,39 @@ public class WifiManager {
         }
     }
 
+    /**
+     * Start SoftAp mode with the specified configuration.
+     * Note that starting in access point mode disables station
+     * mode operation
+     * @param wifiConfig SSID, security and channel details as
+     *        part of WifiConfiguration
+     * @return {@code true} if the operation succeeds, {@code false} otherwise
+     *
+     * @hide
+     */
+    public boolean startSoftAp(@Nullable WifiConfiguration wifiConfig) {
+        try {
+            return mService.startSoftAp(wifiConfig);
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Stop SoftAp mode.
+     * Note that stopping softap mode will restore the previous wifi mode.
+     * @return {@code true} if the operation succeeds, {@code false} otherwise
+     *
+     * @hide
+     */
+    public boolean stopSoftAp() {
+        try {
+            return mService.stopSoftAp();
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
     /**
      * Gets the Wi-Fi enabled state.
      * @return One of {@link #WIFI_AP_STATE_DISABLED},