  var blockLeft = blockToDrag.svgGroup_.getBoundingClientRect().left;

        // Click somewhere on the block.
        var mouseDownEvent = new MouseEvent('mousedown',
            {clientX: blockLeft + 5, clientY: blockTop + 5});
        blockToDrag.onMouseDown_(mouseDownEvent);

        // Throw in a move for good measure.
        setTimeout(
          function() {
            var mouseMoveEvent = new MouseEvent('mousemove',
                {clientX: blockLeft + dx,
                clientY: blockTop + dy}