Rename IndexStore to avoid confusion with the new public API

pkg/analysis_server/lib/src/services/index/index_store.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.index_store;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * A container with information computed by an index - relations between
  * elements.
  */
-abstract class IndexStore {
+abstract class InternalIndexStore {
   /**
    * Answers index statistics.
    */
   String get statistics;
 
   /**
    * Notifies the index store that we are going to index an unit with the given
    * [unitElement].
    *
    * If the unit is a part of a library, then all its locations are removed.
@@ skipping 119 matching lines @@
    * any other elements and a location within the given sources.
    *
    * This method should be invoked when multiple sources are no longer part of
    * the code base.
    *
    * [context] - the [AnalysisContext] in which [Source]s being removed.
    * [container] - the [SourceContainer] holding the sources being removed.
    */
   void removeSources(AnalysisContext context, SourceContainer container);
 }