code: function configureWatchers () {
      var wait = parseInt($scope.delay, 10) || 0;
  
      $attrs.$observe('disabled', function (value) { ctrl.isDisabled = $mdUtil.parseAttributeBoolean(value, false); });
      $attrs.$observe('required', function (value) { ctrl.isRequired = $mdUtil.parseAttributeBoolean(value, false); });
      $attrs.$observe('readonly', function (value) { ctrl.isReadonly = $mdUtil.parseAttributeBoolean(value, false); });
  
      $scope.$watch('searchText', wait ? $mdUtil.debounce(handleSearchText, wait) : handleSearchText);
      $scope.$watch('selectedItem', selectedItemChange);
  
      angular.element($window).on('resize', debouncedOnResize);
  
      $scope.$on('$destroy', cleanup);
    }
docs: Sets up any watchers used by autocomplete