Add support code to make fixes easier in plugins

pkg/analysis_server/lib/src/services/correction/fix_internal.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.
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
 
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_dart.dart';
@@ skipping 26 matching lines @@
 import 'package:analyzer/src/generated/error_verifier.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer_plugin/protocol/protocol_common.dart'
     hide AnalysisError, Element, ElementKind;
 import 'package:analyzer_plugin/src/utilities/string_utilities.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_dart.dart';
+import 'package:analyzer_plugin/utilities/fixes/fixes.dart' hide FixContributor;
 import 'package:analyzer_plugin/utilities/range_factory.dart';
 import 'package:path/path.dart';
 
 /**
  * A predicate is a one-argument function that returns a boolean value.
  */
 typedef bool ElementPredicate(Element argument);
 
 /**
  * The implementation of [DartFixContext].
@@ skipping 3157 matching lines @@
       }
     }
   }
 
   void _updateList(Iterable<Element> elements) {
     for (Element element in elements) {
       _update(element);
     }
   }
 }