move combinator contributor to new task model

pkg/analysis_server/lib/src/services/completion/dart_completion_manager.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.completion.dart;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart'
     show AnalysisRequest, CompletionContributor, CompletionRequest;
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
-import 'package:analysis_server/src/services/completion/combinator_contributor.dart';
 import 'package:analysis_server/src/services/completion/completion_core.dart';
 import 'package:analysis_server/src/services/completion/completion_manager.dart';
 import 'package:analysis_server/src/services/completion/dart/common_usage_sorter.dart';
 import 'package:analysis_server/src/services/completion/dart/contribution_sorter.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
 import 'package:analysis_server/src/services/completion/imported_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/local_reference_contributor.dart';
 import 'package:analysis_server/src/services/completion/optype.dart';
 import 'package:analysis_server/src/services/completion/prefixed_element_contributor.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
@@ skipping 68 matching lines @@
       : super(context, source) {
     if (contributors == null) {
       contributors = [
         // LocalReferenceContributor before ImportedReferenceContributor
         // because local suggestions take precedence
         // and can hide other suggestions with the same name
         new LocalReferenceContributor(),
         new ImportedReferenceContributor(),
         //new KeywordContributor(),
         //new ArgListContributor(),
-        new CombinatorContributor(),
+        // new CombinatorContributor(),
         new PrefixedElementContributor(),
         //new UriContributor(),
         // TODO(brianwilkerson) Use the completion contributor extension point
         // to add the contributor below (and eventually, all the contributors).
 //        new NewCompletionWrapper(new InheritedContributor())
       ];
     }
     if (newContributors == null) {
       newContributors = <CompletionContributor>[];
     }
@@ skipping 369 matching lines @@
               // Replacement range for import URI
               return new ReplacementRange(start, end - start);
             }
           }
         }
       }
     }
     return new ReplacementRange(requestOffset, 0);
   }
 }