Use IndexContributor(s) in LocalIndex.

pkg/analysis_server/test/services/search/hierarchy_test.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 test.services.src.search.hierarchy;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_memory_index.dart';
@@ skipping 298 matching lines @@
     }
     // F
     {
       Set<ClassElement> supers = getSuperClasses(classF);
       expect(supers, unorderedEquals([objectElement, classA]));
     }
   }
 
   void _indexTestUnit(String code) {
     resolveTestUnit(code);
-    index.indexUnit(context, testUnit);
+    index.index(context, testUnit);
   }
 }