Move SourceReference, extract duplicate code.

pkg/analysis_server/lib/src/services/correction/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 services.correction.fix;
 
 import 'package:analysis_server/src/protocol.dart' show SourceChange;
 import 'package:analysis_server/src/services/correction/fix_internal.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/error.dart';
-import 'package:analyzer/src/generated/source.dart';
 
 
 /**
  * Computes [Fix]s for the given [AnalysisError].
  *
  * Returns the computed [Fix]s, not `null`.
  */
 List<Fix> computeFixes(SearchEngine searchEngine, CompilationUnit unit,
     AnalysisError error) {
   var processor = new FixProcessor(searchEngine, unit, error);
@@ skipping 98 matching lines @@
 
   final name;
   final int relevance;
   final String message;
 
   const FixKind(this.name, this.relevance, this.message);
 
   @override
   String toString() => name;
 }