Introduce onLost event on bssid hotlist

Change-Id: I84c3174398fea9a1456fb007586c2c559dd3fe4d
diff --git a/wifi/java/android/net/wifi/WifiScanner.java b/wifi/java/android/net/wifi/WifiScanner.java
index aaa2f98..41b2f4e 100644
--- a/wifi/java/android/net/wifi/WifiScanner.java
+++ b/wifi/java/android/net/wifi/WifiScanner.java
@@ -468,6 +468,10 @@
          * @param results list of scan results, one for each access point visible currently
          */
         public void onFound(ScanResult[] results);
+        /** indicates that access points were missed by on going scans
+         * @param results list of scan results, for each access point that is not visible anymore
+         */
+        public void onLost(ScanResult[] results);
     }
 
     /** @hide */
@@ -813,6 +817,10 @@
                     ((BssidListener) listener).onFound(
                             ((ParcelableScanResults) msg.obj).getResults());
                     return;
+                case CMD_AP_LOST:
+                    ((BssidListener) listener).onLost(
+                            ((ParcelableScanResults) msg.obj).getResults());
+                    return;
                 case CMD_WIFI_CHANGE_DETECTED:
                     ((WifiChangeListener) listener).onChanging(
                             ((ParcelableScanResults) msg.obj).getResults());