createUi(container) {
    container = $(container);
    this.baseEl_ = $('<div>')
        .addClass('form-field-outer')
        .addClass(this.params_.newGroup ? 'is-new-group' : '')
        .append(
          $('<label>')
            .attr('for', this.getHtmlId())
            .text(this.params_.title)
            .append($('<div>')
              .addClass('form-field-help-text')
              .css('display', this.params_.helpText ? '' : 'none')
              .html(this.params_.helpText))
        )
        .append(
          $('<div>')
            .addClass('form-field-container')
        )
        .appendTo(container);
    return this.baseEl_;
  }
Generates the UI elements for a form field container. Not very portable
outside the Asset Studio UI. Intended to be overriden by descendents.
@private
@param {HTMLElement} container The destination element to contain the
field.