Issue 18926. Rename refactoring for labels.

pkg/analysis_server/lib/src/services/refactoring/naming_conventions.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.naming_conventions;
 
 import 'package:analysis_server/src/services/correction/status.dart';
 import 'package:analysis_server/src/services/correction/strings.dart';
 
 
@@ skipping 96 matching lines @@
   }
   return _validateLowerCamelCase(name, "Import prefix");
 }
 
 /**
  * Returns the [RefactoringStatus] with severity:
  *   OK if the name is valid;
  *   WARNING if the name is discouraged;
  *   ERROR if the name is illegal.
  */
+RefactoringStatus validateLabelName(String name) {
+  return _validateLowerCamelCase(name, "Label");
+}
+
+/**
+ * Returns the [RefactoringStatus] with severity:
+ *   OK if the name is valid;
+ *   WARNING if the name is discouraged;
+ *   ERROR if the name is illegal.
+ */
 RefactoringStatus validateLibraryName(String name) {
   // null
   if (name == null) {
     return new RefactoringStatus.fatal("Library name must not be null.");
   }
   // blank
   if (isBlank(name)) {
     return new RefactoringStatus.fatal("Library name must not be blank.");
   }
   // check identifiers
@@ skipping 144 matching lines @@
   }
   // does not start with upper case
   if (!isUpperCase(identifier.codeUnitAt(0))) {
     // By convention, class names usually start with an uppercase letter
     String message = "$desc should start with an uppercase letter.";
     return new RefactoringStatus.warning(message);
   }
   // OK
   return new RefactoringStatus();
 }