code: function positionAbsolutely(element, x, y, extraTransforms) {
    extraTransforms = extraTransforms || '';
    if (cssSupported()) {
      // Use CSS 3D transforms when the browser supports them.
      // A translateZ(0) transform improves performance on Chrome by creating a
      // new layer for the element, which prevents unnecessary repaints.
      var transform = 'translateX(' + decimal(x) + 'px) translateY(' + decimal(y) + 'px) translateZ(0) ' + extraTransforms;
      setTransform(element, transform);
    } else {
      // Fall back to absolute positioning.
      setPixelPosition(element, x, y);
    }
  }
docs: This cannot belong in util/dom.js because support/Css also depends on it and it would cause a circular dependency.