Re-organize and comment clean-up

pkg/analyzer_plugin/lib/utilities/subscription_manager.dart

-// Copyright (c) 2017, 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.
-
-import 'package:analyzer_plugin/protocol/protocol_generated.dart';
-
-/**
- * An object that manages the subscriptions for analysis results.
- */
-class SubscriptionManager {
-  /**
-   * The current set of subscriptions.
-   */
-  Map<AnalysisService, List<String>> _subscriptions;
-
-  /**
-   * Initialize a newly created subscription manager to have no subscriptions.
-   */
-  SubscriptionManager();
-
-  /**
-   * Return a list of the services for which the file with the given [filePath]
-   * has been subscribed.
-   */
-  List<AnalysisService> servicesForFile(String filePath) {
-    List<AnalysisService> services = <AnalysisService>[];
-    if (_subscriptions != null) {
-      _subscriptions.forEach((AnalysisService service, List<String> files) {
-        if (files.contains(filePath)) {
-          services.add(service);
-        }
-      });
-    }
-    return services;
-  }
-
-  /**
-   * Set the current set of subscriptions to those described by the given map of
-   * [subscriptions].
-   */
-  void setSubscriptions(Map<AnalysisService, List<String>> subscriptions) {
-    _subscriptions = subscriptions;
-  }
-}