incremental step moving completion into services and adding tests

pkg/analysis_server/lib/src/domain_completion.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 domain.completion;
 
-import 'dart:async';
-
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_services/completion/completion_suggestion.dart';
+import 'package:analysis_services/completion/top_level_computer.dart';
 import 'package:analysis_services/constants.dart';
 import 'package:analysis_services/search/search_engine.dart';
-import 'package:analyzer/src/generated/element.dart';
 
 /**
  * Instances of the class [CompletionDomainHandler] implement a [RequestHandler]
  * that handles requests in the search domain.
  */
 class CompletionDomainHandler implements RequestHandler {
   /**
    * The analysis server that is using this handler to process requests.
    */
   final AnalysisServer server;
@@ skipping 25 matching lines @@
     }
     return null;
   }
 
   Response getSuggestions(Request request) {
     // extract param
     String file = request.getRequiredParameter(FILE).asString();
     int offset = request.getRequiredParameter(OFFSET).asInt();
     // schedule completion analysis
     String completionId = (_nextCompletionId++).toString();
-    var computer = new TopLevelSuggestionsComputer(server.searchEngine);
+    var computer = new TopLevelComputer(server.searchEngine);
     var future = computer.compute();
     future.then((List<CompletionSuggestion> results) {
       _sendCompletionNotification(completionId, true, results);
     });
     // respond
     return new Response(request.id)..setResult(ID, completionId);
   }
 
   void _sendCompletionNotification(String completionId, bool isLast,
       Iterable<CompletionSuggestion> results) {
     Notification notification = new Notification(COMPLETION_RESULTS);
     notification.setParameter(ID, completionId);
     notification.setParameter(LAST, isLast);
     notification.setParameter(RESULTS, results);
     server.sendNotification(notification);
   }
 }
 
-/**
- * A computer for `completion.getSuggestions` request results.
- */
-class TopLevelSuggestionsComputer {
-  final SearchEngine searchEngine;
-
-  TopLevelSuggestionsComputer(this.searchEngine);
-
-  /**
-   * Computes [CompletionSuggestion]s for the specified position in the source.
-   */
-  Future<List<CompletionSuggestion>> compute() {
-    var future = searchEngine.searchTopLevelDeclarations('');
-    return future.then((List<SearchMatch> matches) {
-      return matches.map((SearchMatch match) {
-        Element element = match.element;
-        String completion = element.displayName;
-        return new CompletionSuggestion(
-            CompletionSuggestionKind.fromElementKind(element.kind),
-            CompletionRelevance.DEFAULT,
-            completion,
-            completion.length,
-            0,
-            element.isDeprecated,
-            false // isPotential
-            );
-      }).toList();
-    });
-  }
-}