removeSubview(view) {
    const subviewIndex = this.subviews.indexOf(view);

    if (subviewIndex === -1) {
      return;
    }

    view.superview = undefined;
    this.subviews.splice(subviewIndex, 1);
  }
Breaks the subview-superview relationship between `view` and this view, if
`view` is a subview of this view.