/**
  * Called when the item is assumed to be gone for good. Remove the graphic annotation from the
  * overlay.
  */
 @Override
 public void onDone() {
   mOverlay.remove(mGraphic);
 }
 /**
  * Hide the graphic when the corresponding face was not detected. This can happen for intermediate
  * frames temporarily, for example if the face was momentarily blocked from view.
  */
 @Override
 public void onMissing(Detector.Detections<T> detectionResults) {
   mOverlay.remove(mGraphic);
 }