ssertWidthAndHeight(offscreencanvas, "resized offscreencanvas", 30, 40);
  var imagebitmap = offscreencanvas.transferToImageBitmap();
  assertWidthAndHeight(imagebitmap, "imagebitmap transferred from resized offscreencanvas" , 30, 40);

  // Verify that setting the size of an OffscreenCanvas does not directly update the size of its placeholder canvas.
  assertWidthAndHeight(placeholder, "placeholder canvas", 10, 20);

  var asyncStepsCompleted = 0;
  ctx.commit();
  createImageBitmap(placeholder).then(image