anchor.diff:  /// Virtual DOM Text Input Element
   class VTextInput extends VElementBase<html.InputElement> {
     final String _value;
  +  final String placeholder;
  +  final bool autofocus;
   
     String get value => ref.value;
   
     VTextInput({
       Object key,
       String value,
  +    this.placeholder,
  +    this.autofocus,
       String id,
       Map<String, String> attributes,
       List<String> classes,
  
positive.code: VTextInput textInput({
    Object key,
    String value,
    String id,
    Map<String, String> attributes,
    List<String> classes,
  
negative.code:     if (other._value != null && ref.value != other._value) {
        ref.value = other._value;
      }
      if (other.placeholder != placeholder) {
        ref.placeholder = other.placeholder;
      }
      // no need to update autofocus when element is already created.
    }
  }
  