A callback that is used to set the position of a {@link PopupPanel} right before it is shown.

abstract class PopupPanelPositionCallback {

 /**
  * Provides the opportunity to set the position of the PopupPanel right
  * before the PopupPanel is shown. The offsetWidth and offsetHeight values
  * of the PopupPanel are made available to allow for positioning based on
  * its size.
 *
  * @param offsetWidth the offsetWidth of the PopupPanel
  * @param offsetHeight the offsetHeight of the PopupPanel
  * @see PopupPanel#setPopupPositionAndShow(PositionCallback)
  */
 void setPosition(int offsetWidth, int offsetHeight);
}