Implement SearchEngine.searchAllSubtypes() with the analysis driver.

pkg/analysis_server/lib/src/services/search/search_engine_internal2.dart

 // Copyright (c) 2016, 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.
 
 import 'dart:async';
 
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/analysis/search.dart';
 import 'package:analyzer/src/generated/source.dart' show Source, SourceRange;
 
 /**
  * A [SearchEngine] implementation.
  */
 class SearchEngineImpl2 implements SearchEngine {
   final Iterable<AnalysisDriver> _drivers;
 
   SearchEngineImpl2(this._drivers);
 
   @override
-  Future<List<SearchMatch>> searchAllSubtypes(ClassElement type) async {
-    // TODO(scheglov) implement
-    return [];
+  Future<Set<ClassElement>> searchAllSubtypes(ClassElement type) async {
+    Set<ClassElement> allSubtypes = new Set<ClassElement>();
+
+    Future<Null> addSubtypes(ClassElement type) async {
+      List<SearchResult> directResults = await _searchDirectSubtypes(type);
+      for (SearchResult directResult in directResults) {
+        var directSubtype = directResult.enclosingElement as ClassElement;
+        if (allSubtypes.add(directSubtype)) {
+          await addSubtypes(directSubtype);
+        }
+      }
+    }
+
+    await addSubtypes(type);
+    return allSubtypes;
   }
 
   @override
   Future<List<SearchMatch>> searchMemberDeclarations(String name) async {
     // TODO(scheglov) implement
     return [];
   }
 
   @override
   Future<List<SearchMatch>> searchMemberReferences(String name) async {
     // TODO(scheglov) implement
     return [];
   }
 
   @override
   Future<List<SearchMatch>> searchReferences(Element element) async {
     List<SearchResult> allResults = [];
     for (AnalysisDriver driver in _drivers) {
       List<SearchResult> results = await driver.search.references(element);
       allResults.addAll(results);
     }
     return allResults.map(_SearchMatch.forSearchResult).toList();
   }
 
   @override
   Future<List<SearchMatch>> searchSubtypes(ClassElement type) async {
-    List<SearchResult> allResults = [];
-    for (AnalysisDriver driver in _drivers) {
-      List<SearchResult> results = await driver.search.subTypes(type);
-      allResults.addAll(results);
-    }
-    return allResults.map(_SearchMatch.forSearchResult).toList();
+    List<SearchResult> results = await _searchDirectSubtypes(type);
+    return results.map(_SearchMatch.forSearchResult).toList();
   }
 
   @override
   Future<List<SearchMatch>> searchTopLevelDeclarations(String pattern) async {
     // TODO(scheglov) implement
     return [];
   }
+
+  Future<List<SearchResult>> _searchDirectSubtypes(ClassElement type) async {
+    List<SearchResult> allResults = [];
+    for (AnalysisDriver driver in _drivers) {
+      List<SearchResult> results = await driver.search.subTypes(type);
+      allResults.addAll(results);
+    }
+    return allResults;
+  }
 }
 
 class _SearchMatch implements SearchMatch {
   @override
   final String file;
 
   @override
   final Source librarySource;
 
   @override
@@ skipping 70 matching lines @@
     }
     if (kind == SearchResultKind.WRITE) {
       return MatchKind.WRITE;
     }
     if (kind == SearchResultKind.INVOCATION) {
       return MatchKind.INVOCATION;
     }
     return MatchKind.REFERENCE;
   }
 }