Add quick-fix to convert child: to children:

pkg/analysis_server/test/services/correction/flutter_util.dart

+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library test.services.correction.flutter_util;
+
+String flutterPkgLibPath = '/packages/flutter/lib';
+
+String get flutter_framework_code => '''
+class Widget {}
+class RenderObjectWidget extends Widget {}
+class StatelessWidget extends Widget {}
+class SingleChildRenderObjectWidget extends RenderObjectWidget {}
+class Transform extends SingleChildRenderObjectWidget {}
+class ClipRect extends SingleChildRenderObjectWidget { ClipRect.rect(){} }
+class AspectRatio extends SingleChildRenderObjectWidget {}
+class Container extends StatelessWidget { Container({child: null, width: null, height: null}){}}
+class Center extends StatelessWidget { Center({child: null, key: null}){}}
+class DefaultTextStyle extends StatelessWidget { DefaultTextStyle({child: null}){}}
+class Row extends Widget { Row({children: null}){}}
+class GestureDetector extends SingleChildRenderObjectWidget { GestureDetector({child: null, onTap: null}){}}
+class Scaffold extends Widget { Scaffold({body: null}){}}
+''';