Return empty scan results for background user

Bug: 7087342
Change-Id: I62493e5004111311b7ac9b7610c85e6784e2c7e4
diff --git a/services/java/com/android/server/WifiService.java b/services/java/com/android/server/WifiService.java
index 7ed4f8a..c139e0c 100644
--- a/services/java/com/android/server/WifiService.java
+++ b/services/java/com/android/server/WifiService.java
@@ -16,6 +16,7 @@
 
 package com.android.server;
 
+import android.app.ActivityManager;
 import android.app.AlarmManager;
 import android.app.Notification;
 import android.app.NotificationManager;
@@ -55,6 +56,7 @@
 import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.SystemProperties;
+import android.os.UserHandle;
 import android.os.WorkSource;
 import android.provider.Settings;
 import android.text.TextUtils;
@@ -834,7 +836,11 @@
      */
     public List<ScanResult> getScanResults() {
         enforceAccessPermission();
-        return mWifiStateMachine.syncGetScanResultsList();
+        if (UserHandle.getCallingUserId() != ActivityManager.getCurrentUser()) {
+            return new ArrayList<ScanResult>();
+        } else {
+            return mWifiStateMachine.syncGetScanResultsList();
+        }
     }
 
     /**