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);
  }
Sets up any watchers used by autocomplete