d attributes for binding if needed

      /**
       * Bind this to the `<input is="iron-input">`'s `autocapitalize` property.
       */
      autocapitalize: {
        type: String,
        value: 'none'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autocorrect` property.
       */
      autocorrect: {
        type: String,
        value: 'off'
      },

      /**
       * Bind this to the `<input is="iron-input">`'s `autosave` property, used with type=search.
       */
      a