// Call to drag a promised file to the given path (should be called before
// -endDragAt:...); hook up to -namesOfPromisedFilesDroppedAtDestination:.
// Returns the file name (not including path) of the file deposited (or which
// Call to drag a promised file to the given path (should be called before
// -endDragAt:...); hook up to -namesOfPromisedFilesDroppedAtDestination:.
// Returns the file name (not including path) of the file deposited (or which