Record HAS_ANCESTOR relations into index.

pkg/analysis_server/lib/src/services/search/search_engine_internal.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.search.search_engine;
 
 import 'dart:async';
 
 import 'package:analysis_server/analysis/index_core.dart';
 import 'package:analysis_server/src/services/correction/source_range.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/indexable_element.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * A [SearchEngine] implementation.
  */
 class SearchEngineImpl implements SearchEngine {
   final Index _index;
 
   SearchEngineImpl(this._index);
 
   @override
+  Future<List<SearchMatch>> searchAllSubtypes(ClassElement type) {
+    _Requestor requestor = new _Requestor(_index);
+    requestor.addElement(
+        type, IndexConstants.HAS_ANCESTOR, MatchKind.DECLARATION);
+    return requestor.merge();
+  }
+
+  @override
   Future<List<SearchMatch>> searchElementDeclarations(String name) {
     IndexableName indexableName = new IndexableName(name);
     _Requestor requestor = new _Requestor(_index);
     requestor.add(indexableName, IndexConstants.NAME_IS_DEFINED_BY,
         MatchKind.DECLARATION);
     return requestor.merge();
   }
 
   @override
   Future<List<SearchMatch>> searchMemberDeclarations(String name) {
@@ skipping 203 matching lines @@
     IndexableElement indexable = new IndexableElement(element);
     add(indexable, relationship, kind);
   }
 
   Future<List<SearchMatch>> merge() {
     return Future.wait(futures).then((List<List<SearchMatch>> matchesList) {
       return matchesList.expand((matches) => matches).toList();
     });
   }
 }