code: function (width) {
              var so = this._width;
              ariaTemplatesLayout.setSOViewport(so, width);
              if (this._tpl.$width != so.value) {
                  this._tpl.$width = so.value;
                  return true;
              }
              return false;
          }
docs: Set the actual width of the template so that $hdim can work properly. This method is intended to be
  called only from the generated code of templates (created in aria.templates.ClassGenerator) and never
  directly from developer code.
  @private