Move index closer to the plugin API

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/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;
 
@@ skipping 170 matching lines @@
   }
 }
 
 class _Requestor {
   final List<Future<List<SearchMatch>>> futures = <Future<List<SearchMatch>>>[];
   final Index index;
 
   _Requestor(this.index);
 
   void add(Element element, RelationshipImpl relationship, MatchKind kind) {
-    Future relationsFuture = index.getRelationships(element, relationship);
+    Future relationsFuture =
+        index.getRelationships(new IndexableElement(element), relationship);
     Future matchesFuture = relationsFuture.then((List<LocationImpl> locations) {
       List<SearchMatch> matches = <SearchMatch>[];
       for (LocationImpl location in locations) {
-        matches.add(new SearchMatch(kind, location.element,
-            new SourceRange(location.offset, location.length),
-            location.isResolved, location.isQualified));
+        IndexableObject indexable = location.indexable;
+        if (indexable is IndexableElement) {
+          matches.add(new SearchMatch(kind, indexable.element,
+              new SourceRange(location.offset, location.length),
+              location.isResolved, location.isQualified));
+        }
       }
       return matches;
     });
     futures.add(matchesFuture);
   }
 
   Future<List<SearchMatch>> merge() {
     return Future.wait(futures).then((List<List<SearchMatch>> matchesList) {
       return matchesList.expand((matches) => matches).toList();
     });
   }
 }