Set flag to disallow non system window overlays to prevent tapjacking

Bug: 183609798
Test: manual
Change-Id: Id2f3262142817a6eccad902913d69bcf2c3f6c60

packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingSecondaryUserActivity.java

@@ -30,6 +30,7 @@ import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.SystemProperties;
 import android.util.Log;
+import android.view.WindowManager;
 
 import com.android.internal.app.AlertActivity;
 import com.android.internal.app.AlertController;
@@ -51,6 +52,8 @@ public class UsbDebuggingSecondaryUserActivity extends AlertActivity
 
     @Override
     public void onCreate(Bundle icicle) {
+        getWindow().addSystemFlags(
+                WindowManager.LayoutParams.SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
         super.onCreate(icicle);
 
         if (SystemProperties.getInt("service.adb.tcp.port", 0) == 0) {