Add defaultCompletionSorter allowing sorting to be overridden - fixes #24339

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

Index: pkg/analysis_server/lib/src/services/completion/contribution_sorter.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/contribution_sorter.dart b/pkg/analysis_server/lib/src/services/completion/contribution_sorter.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a702f66921c5bcd014674e0e55e65852fd83618b
--- /dev/null
+++ b/pkg/analysis_server/lib/src/services/completion/contribution_sorter.dart
@@ -0,0 +1,25 @@
+// 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.sorter;
+
+import 'package:analysis_server/src/protocol.dart';
+import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
+
+/**
+ * The abstract class `ContributionSorter` defines the behavior of objects
+ * that are used to adjust the relevance of an existing list of suggestions.
+ * This is a long-lived object that should not maintain state between
+ * calls to it's [sort] method.
+ */
+abstract class ContributionSorter {
+  /**
+   * After [CompletionSuggestion]s have been computed,
+   * this method is called to adjust the relevance of those suggestions.
+   * The compilation unit and completion node
+   * in the given completion context may not be resolved.
+   * This method should execute quickly and not block.
+   */
+  void sort(DartCompletionRequest request);
+}