move dart completion contributor instantiation

pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart

 // Copyright (c) 2015, 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.completion.dart.manager;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart'
@@ skipping 26 matching lines @@
     }
     return new Future.value();
   }
 
   /**
    * Return a [Future] that completes with a list of suggestions
    * for the given completion [request].
    */
   Future<List<CompletionSuggestion>> _computeDartSuggestions(
       DartCompletionRequest request) async {
-    // Build the Dart specific completion contributors
-    List<DartCompletionContributor> contributors =
-        <DartCompletionContributor>[];
-    for (DartCompletionContributorFactory contributorFactory
-        in dartCompletionPlugin.contributorFactories) {
-      contributors.add(contributorFactory());
-    }
-
     // Request Dart specific completions from each contributor
     List<CompletionSuggestion> suggestions = <CompletionSuggestion>[];
-    for (DartCompletionContributor contributor in contributors) {
-      suggestions.addAll(await contributor.computeSuggestions(request));
+    for (DartCompletionContributor c in dartCompletionPlugin.contributors) {
+      suggestions.addAll(await c.computeSuggestions(request));
     }
     return suggestions;
   }
 }
 
 /**
  * The information about a requested list of completions within a Dart file.
  */
 class DartCompletionRequestImpl extends CompletionRequestImpl
     implements DartCompletionRequest {
@@ skipping 71 matching lines @@
 
   @override
   CompletionTarget get target {
     if (_target == null) {
       CompilationUnit unit = context.computeResult(source, PARSED_UNIT);
       _target = new CompletionTarget.forOffset(unit, offset);
     }
     return _target;
   }
 }