updateValues method
Called whenever chip is either added or removed from the outside the context of the text field.
Implementation
void updateValues(List<T> values) {
if (values.length != this.values.length) {
final String char = String.fromCharCode(kObjectReplacementChar);
final int length = values.length;
value = TextEditingValue(
text: char * length,
selection: TextSelection.collapsed(offset: length),
);
this.values = values;
}
}