Move Index and IndexStore implementations into Engine.

pkg/analyzer/test/index/store/single_source_container.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.index.store_single_source_container;
+library test.engine.src.index.store_single_source_container;
 
 import 'package:analyzer/src/generated/source.dart';
 
 
 /**
  * A [SourceContainer] with a single [Source].
  */
 class SingleSourceContainer implements SourceContainer {
   final Source _source;
 
   SingleSourceContainer(this._source);
 
   @override
   bool contains(Source source) => source == _source;
 }