Add quick-fix to convert child: to children:

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

 // Copyright (c) 2014, 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.fix;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
 import 'package:analysis_server/plugin/protocol/protocol.dart'
     hide AnalysisError;
 import 'package:analysis_server/src/services/correction/fix.dart';
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/dart/analysis/ast_provider_driver.dart';
 import 'package:analyzer/src/dart/element/ast_provider.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import '../../abstract_single_unit.dart';
+import 'flutter_util.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(FixProcessorTest);
     defineReflectiveTests(LintFixTest);
     defineReflectiveTests(FixProcessorTest_Driver);
     defineReflectiveTests(LintFixTest_Driver);
   });
 }
 
 typedef bool AnalysisErrorFilter(AnalysisError error);
 
 /**
  * Base class for fix processor tests.
  */
 class BaseFixProcessorTest extends AbstractSingleUnitTest {
   AnalysisErrorFilter errorFilter = (AnalysisError error) {
     return error.errorCode != HintCode.UNUSED_CATCH_CLAUSE &&
         error.errorCode != HintCode.UNUSED_CATCH_STACK &&
         error.errorCode != HintCode.UNUSED_ELEMENT &&
         error.errorCode != HintCode.UNUSED_FIELD &&
         error.errorCode != HintCode.UNUSED_LOCAL_VARIABLE;
   };
 
   String myPkgLibPath = '/packages/my_pkg/lib';
 
+  String flutterPkgLibPath = '/packages/flutter/lib';
+
   Fix fix;
   SourceChange change;
   String resultCode;
 
   assert_undefinedFunction_create_returnType_bool(String lineWithTest) async {
     await resolveTestUnit('''
 main() {
   bool b = true;
   $lineWithTest
 }
@@ skipping 5314 matching lines @@
         '''
 class A {
   myMethod() {}
   main() {
     myMethod();
   }
 }
 ''');
   }
 
+  test_undefinedParameter_convertFlutterChild_invalidList() async {
+    _configureFlutterPkg({
+      'src/widgets/framework.dart': flutter_framework_code,
+    });
+    await resolveTestUnit('''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Container(
+    child: new Row(
+      child: <Widget>[
+        new Transform(),
+        null,
+        new AspectRatio(),
+      ],
+    ),
+  );
+}
+''');
+    await assertNoFix(DartFixKind.CONVERT_FLUTTER_CHILD);
+  }
+
+  test_undefinedParameter_convertFlutterChild_OK_hasList() async {
+    _configureFlutterPkg({
+      'src/widgets/framework.dart': flutter_framework_code,
+    });
+    await resolveTestUnit('''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Container(
+    child: new Row(
+      child: [
+        new Transform(),
+        new ClipRect.rect(),
+        new AspectRatio(),
+      ],
+    ),
+  );
+}
+''');
+    await assertHasFix(
+        DartFixKind.CONVERT_FLUTTER_CHILD,
+        '''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Container(
+    child: new Row(
+      children: <Widget>[
+        new Transform(),
+        new ClipRect.rect(),
+        new AspectRatio(),
+      ],
+    ),
+  );
+}
+''');
+  }
+
+  test_undefinedParameter_convertFlutterChild_OK_hasTypedList() async {
+    _configureFlutterPkg({
+      'src/widgets/framework.dart': flutter_framework_code,
+    });
+    await resolveTestUnit('''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Container(
+    child: new Row(
+      child: <Widget>[
+        new Transform(),
+        new ClipRect.rect(),
+        new AspectRatio(),
+      ],
+    ),
+  );
+}
+''');
+    await assertHasFix(
+        DartFixKind.CONVERT_FLUTTER_CHILD,
+        '''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Container(
+    child: new Row(
+      children: <Widget>[
+        new Transform(),
+        new ClipRect.rect(),
+        new AspectRatio(),
+      ],
+    ),
+  );
+}
+''');
+  }
+
+  test_undefinedParameter_convertFlutterChild_OK_multiLine() async {
+    _configureFlutterPkg({
+      'src/widgets/framework.dart': flutter_framework_code,
+    });
+    await resolveTestUnit('''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Scaffold(
+    body: new Row(
+      child: new Container(
+        width: 200.0,
+        height: 300.0,
+      ),
+    ),
+  );
+}
+''');
+    await assertHasFix(
+        DartFixKind.CONVERT_FLUTTER_CHILD,
+        '''
+import 'package:flutter/src/widgets/framework.dart';
+build() {
+  return new Scaffold(
+    body: new Row(
+      children: <Widget>[
+        new Container(
+          width: 200.0,
+          height: 300.0,
+        ),
+      ],
+    ),
+  );
+}
+''');
+  }
+
   test_undefinedSetter_useSimilar_hint() async {
     await resolveTestUnit('''
 class A {
   int myField;
 }
 main(A a) {
   var x = a;
   x.myFild = 42;
 }
 ''');
@@ skipping 117 matching lines @@
 library meta;
 
 const Required required = const Required();
 
 class Required {
   final String reason;
   const Required([this.reason]);
 }
 ''');
   }
+
+  /**
+   * Configures the [SourceFactory] to have the `flutter` package in
+   * `/packages/flutter/lib` folder.
+   */
+  void _configureFlutterPkg(Map<String, String> pathToCode) {
+    pathToCode.forEach((path, code) {
+      provider.newFile('$flutterPkgLibPath/$path', code);
+    });
+    // configure SourceFactory
+    Folder myPkgFolder = provider.getResource(flutterPkgLibPath);
+    UriResolver pkgResolver = new PackageMapUriResolver(provider, {
+      'flutter': [myPkgFolder]
+    });
+    SourceFactory sourceFactory = new SourceFactory(
+        [new DartUriResolver(sdk), pkgResolver, resourceResolver]);
+    if (enableNewAnalysisDriver) {
+      driver.configure(sourceFactory: sourceFactory);
+    } else {
+      context.sourceFactory = sourceFactory;
+    }
+    // force 'flutter' resolution
+    addSource(
+        '/tmp/other.dart',
+        pathToCode.keys
+            .map((path) => "import 'package:flutter/$path';")
+            .join('\n'));
+  }
 }
 
 @reflectiveTest
 class FixProcessorTest_Driver extends FixProcessorTest {
   @override
   bool get enableNewAnalysisDriver => true;
 
   @failingTest
   @override
   test_importLibrarySdk_withClass_AsExpression() {
@@ skipping 305 matching lines @@
 
   @override
   final CompilationUnit unit;
 
   @override
   final AnalysisError error;
 
   _DartFixContextImpl(this.resourceProvider, this.getTopLevelDeclarations,
       this.analysisContext, this.astProvider, this.unit, this.error);
 }