Make more use of generated code in analysis server.

pkg/analysis_server/lib/src/edit/fix.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 edit.fix;
-
-import 'package:analysis_server/src/constants.dart';
-import 'package:analysis_server/src/protocol2.dart';
-import 'package:analysis_server/src/services/correction/change.dart';
-import 'package:analysis_server/src/services/correction/fix.dart';
-import 'package:analysis_server/src/services/json.dart';
-
-
-class ErrorFixes implements HasToJson {
-  final AnalysisError error;
-  final List<Change> fixes = <Change>[];
-
-  ErrorFixes(this.error);
-
-  void addFix(Fix fix) {
-    Change change = fix.change;
-    fixes.add(change);
-  }
-
-  @override
-  Map<String, Object> toJson() {
-    return {
-      ERROR: error.toJson(),
-      FIXES: objectToJson(fixes)
-    };
-  }
-
-  @override
-  String toString() => 'ErrorFixes(error=$error, fixes=$fixes)';
-}