verticallyStackedLayout: Layouter = (layout, containerFrame) => {
  let currentY = containerFrame.origin.y;
  return layout.map(layoutInfo => {
    const desiredSize = layoutInfo.view.desiredSize();
    const height = desiredSize
      ? desiredSize.height
      : containerFrame.origin.y + containerFrame.size.height - currentY;
    const proposedFrame = {
      origin: {x: containerFrame.origin.x, y: currentY},
      size: {width: containerFrame.size.width, height},
    };
    currentY += height;
    return {
      ...layoutInfo,
      frame: proposedFrame,
    };
  });
}
Stacks `views` vertically in `frame`.
All views in `views` will have their widths set to the frame's width.