code: function validateMode() {
        if (angular.isUndefined(attr.mdMode)) {
          var hasValue = angular.isDefined(attr.value);
          var mode = hasValue ? MODE_DETERMINATE : MODE_INDETERMINATE;
          var info = "Auto-adding the missing md-mode='{0}' to the ProgressLinear element";
          element.attr("md-mode", mode);
          attr.mdMode = mode;
        }
      }
docs: Auto-defaults the mode to either `determinate` or `indeterminate` mode; if not specified