More strong mode changes to analysis_server

pkg/analysis_server/lib/src/services/refactoring/rename_class_member.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_class_member;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
@@ skipping 45 matching lines @@
         new _ClassMemberValidator.forRename(searchEngine, element, newName);
     return _validator.validate();
   }
 
   @override
   Future<RefactoringStatus> checkInitialConditions() async {
     RefactoringStatus result = await super.checkInitialConditions();
     if (element is MethodElement && (element as MethodElement).isOperator) {
       result.addFatalError('Cannot rename operator.');
     }
-    return new Future.value(result);
+    return new Future<RefactoringStatus>.value(result);
   }
 
   @override
   RefactoringStatus checkNewName() {
     RefactoringStatus result = super.checkNewName();
     if (element is FieldElement) {
       result.addStatus(validateFieldName(newName));
     }
     if (element is MethodElement) {
       result.addStatus(validateMethodName(newName));
@@ skipping 231 matching lines @@
     }
   }
 }
 
 class _MatchShadowedByLocal {
   final SearchMatch match;
   final LocalElement localElement;
 
   _MatchShadowedByLocal(this.match, this.localElement);
 }