hook new DartCompletionContributor API into existing framework

pkg/analysis_server/lib/src/provisional/completion/completion_dart.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 analysis_server.src.provisional.completion.completion_dart;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
 import 'package:analyzer/src/generated/ast.dart';
 
+export 'package:analysis_server/src/provisional/completion/completion_core.dart'
+    show EMPTY_LIST;
+
+const int DART_RELEVANCE_COMMON_USAGE = 1200;
+const int DART_RELEVANCE_DEFAULT = 1000;
+const int DART_RELEVANCE_HIGH = 2000;
+const int DART_RELEVANCE_INHERITED_ACCESSOR = 1057;
+const int DART_RELEVANCE_INHERITED_FIELD = 1058;
+const int DART_RELEVANCE_INHERITED_METHOD = 1057;
+const int DART_RELEVANCE_KEYWORD = 1055;
+const int DART_RELEVANCE_LOCAL_ACCESSOR = 1057;
+const int DART_RELEVANCE_LOCAL_FIELD = 1058;
+const int DART_RELEVANCE_LOCAL_FUNCTION = 1056;
+const int DART_RELEVANCE_LOCAL_METHOD = 1057;
+const int DART_RELEVANCE_LOCAL_TOP_LEVEL_VARIABLE = 1056;
+const int DART_RELEVANCE_LOCAL_VARIABLE = 1059;
+const int DART_RELEVANCE_LOW = 500;
+const int DART_RELEVANCE_NAMED_PARAMETER = 1060;
+const int DART_RELEVANCE_PARAMETER = 1059;
+
 /**
  * An object used to produce completions
  * at a specific location within a Dart file.
  *
  * Clients may implement this class when implementing plugins.
  */
 abstract class DartCompletionContributor {
   /**
    * Return a [Future] that completes with a list of suggestions
    * for the given completion [request].
@@ skipping 17 matching lines @@
   /**
    * Return a [Future] that completes with a compilation unit in which
    * all declarations in all scopes containing [target] have been resolved.
    * The [Future] may return `null` if the unit cannot be resolved
    * (e.g. unlinked part file).
    * Any information obtained from [target] prior to calling this method
    * should be discarded as it may have changed.
    */
   Future<CompilationUnit> resolveDeclarationsInScope();
 }