code: function setCursor_(a) {
      if(a) {
        src.style.cursor = draggingCursor_;
      } else {
        src.style.cursor = draggableCursor_;
      }
    }
docs: Set the cursor for {@link src} based on whether or not
  the element is currently being dragged.
  @param {Boolean} a Is the element being dragged?
  @private