consumeImageBitmap(image, t)
{
    var myCanvas = document.createElement('canvas');
    myCanvas.width = myCanvas.height = 20;
    var myCtx = myCanvas.getContext('bitmaprenderer');
    myCtx.transferFromImageBitmap(image);

    createImageBitmap(myCanvas).then(t.step_func_done(function(imageBitmap) {
        // Per spec, when transferFromImageBitmap happens, the transferred
        // ImageBitmap (|image| here) must determine the intrinsic size of
        // myCanvas, and hence myCanvas.width/height is ign