Record HAS_ANCESTOR relations into index.

pkg/analysis_server/lib/src/services/search/search_engine.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.search_engine;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/search/search_engine_internal.dart';
@@ skipping 50 matching lines @@
   @override
   String toString() => name;
 }
 
 /**
  * The interface [SearchEngine] defines the behavior of objects that can be used
  * to search for various pieces of information.
  */
 abstract class SearchEngine {
   /**
+   * Returns all subtypes of the given [type].
+   *
+   * [type] - the [ClassElement] being subtyped by the found matches.
+   */
+  Future<List<SearchMatch>> searchAllSubtypes(ClassElement type);
+
+  /**
    * Returns declarations of elements with the given name.
    *
    * [name] - the name being declared by the found matches.
    */
   Future<List<SearchMatch>> searchElementDeclarations(String name);
 
   /**
    * Returns declarations of class members with the given name.
    *
    * [name] - the name being declared by the found matches.
    */
   Future<List<SearchMatch>> searchMemberDeclarations(String name);
 
   /**
    * Returns all resolved and unresolved qualified references to the class
    * members with given [name].
    *
    * [name] - the name being referenced by the found matches.
    */
   Future<List<SearchMatch>> searchMemberReferences(String name);
 
   /**
    * Returns references to the given [Element].
    *
    * [element] - the [Element] being referenced by the found matches.
    */
   Future<List<SearchMatch>> searchReferences(Element element);
 
   /**
-   * Returns subtypes of the given [type].
+   * Returns direct subtypes of the given [type].
    *
    * [type] - the [ClassElement] being subtyped by the found matches.
    */
   Future<List<SearchMatch>> searchSubtypes(ClassElement type);
 
   /**
    * Returns all the top-level declarations matching the given pattern.
    *
    * [pattern] the regular expression used to match the names of the
    *    declarations to be found.
@@ skipping 62 matching lines @@
     buffer.write(", range=");
     buffer.write(sourceRange);
     buffer.write(", isResolved=");
     buffer.write(isResolved);
     buffer.write(", isQualified=");
     buffer.write(isQualified);
     buffer.write(")");
     return buffer.toString();
   }
 }