anchor.diff:            child: ButtonBar(
               layoutBehavior: ButtonBarLayoutBehavior.constrained,
               children: <Widget>[
  -              FlatButton(
  +              TextButton(
                   onPressed: _handleCancel,
                   child: Text(widget.cancelText ?? localizations.cancelButtonLabel),
                 ),
  -              FlatButton(
  +              TextButton(
                   onPressed: _handleOk,
                   child: Text(widget.confirmText ?? localizations.okButtonLabel),
                 ),
  
positive.code: import 'debug.dart';
  import 'dialog.dart';
  import 'feedback.dart';
  import 'flat_button.dart';
  import 'icon_button.dart';
  import 'icons.dart';
  import 'ink_well.dart';
  
negative.code: import 'material.dart';
  import 'material_localizations.dart';
  import 'material_state.dart';
  import 'text_button.dart';
  import 'text_form_field.dart';
  import 'text_theme.dart';
  import 'theme.dart';
  