code: public void adjustGlassSize() {
          if (isGlassEnabled()) {
              ResizeHandler handler = getGlassResizer();
              if (handler != null) handler.onResize(null);
          }
      }
docs: This can be called to adjust the size of the dialog glass. It
  is implemented using JSNI to bypass the "private" keyword on
  the glassResizer.