Fix warning in analyzer2dart.

pkg/analyzer2dart/lib/src/util.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.
 
 // Utility function shared between different parts of analyzer2dart.
 
 library analyzer2dart.util;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 11 matching lines @@
       arity++;
     }
   }
   return new Selector.call(name, null, arity, namedArguments);
 }
 
 /// Prints [message] together with source code pointed to by [node] from
 /// [source].
 void reportSourceMessage(Source source, AstNode node, String message) {
   SourceFile sourceFile =
-      new StringSourceFile(source.fullName, source.contents.data);
+      new StringSourceFile.fromName(source.fullName, source.contents.data);
 
   print(sourceFile.getLocationMessage(message, node.offset, node.end));
 }