Issue 18926. Rename refactoring for labels.

pkg/analysis_server/lib/src/services/refactoring/rename_label.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.src.refactoring.rename_library;
+library services.src.refactoring.rename_label;
 
 import 'dart:async';
 
-import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/src/protocol.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
+import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring.dart';
+import 'package:analysis_server/src/services/refactoring/rename.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
-import 'package:analysis_server/src/services/refactoring/naming_conventions.dart';
-import 'package:analysis_server/src/services/refactoring/rename.dart';
 import 'package:analyzer/src/generated/element.dart';
 
 
 /**
- * A [Refactoring] for renaming [LibraryElement]s.
+ * A [Refactoring] for renaming [LabelElement]s.
  */
-class RenameLibraryRefactoringImpl extends RenameRefactoringImpl {
-  RenameLibraryRefactoringImpl(SearchEngine searchEngine,
-      LibraryElement element)
+class RenameLabelRefactoringImpl extends RenameRefactoringImpl {
+  RenameLabelRefactoringImpl(SearchEngine searchEngine, LabelElement element)
       : super(searchEngine, element);
 
   @override
-  LibraryElement get element => super.element as LibraryElement;
+  LabelElement get element => super.element as LabelElement;
 
   @override
-  String get refactoringName {
-    return "Rename Library";
-  }
+  String get refactoringName => "Rename Label";
 
   @override
   Future<RefactoringStatus> checkFinalConditions() {
     RefactoringStatus result = new RefactoringStatus();
     return new Future.value(result);
   }
 
   @override
   RefactoringStatus checkNewName() {
     RefactoringStatus result = super.checkNewName();
-    result.addStatus(validateLibraryName(newName));
+    result.addStatus(validateLabelName(newName));
     return result;
   }
 
   @override
   Future<SourceChange> createChange() {
     SourceChange change = new SourceChange(refactoringName);
     // update declaration
     addDeclarationEdit(change, element);
     // update references
     return searchEngine.searchReferences(element).then((refMatches) {
       List<SourceReference> references = getSourceReferences(refMatches);
       for (SourceReference reference in references) {
         addReferenceEdit(change, reference);
       }
       return change;
     });
   }
 }