Make it safe to initialize the notificationManager in server

pkg/analysis_server/lib/src/analysis_server.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 analysis.server;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core';
 import 'dart:io' as io;
@@ skipping 108 matching lines @@
    * The channel from which requests are received and to which responses should
    * be sent.
    */
   final ServerCommunicationChannel channel;
 
   /**
    * The object used to manage sending a subset of notifications to the client.
    * The subset of notifications are those to which plugins may contribute.
    * This field is `null` when the new plugin support is disabled.
    */
-  final NotificationManager notificationManager = null;
+  final NotificationManager notificationManager;
 
   /**
    * The [ResourceProvider] using which paths are converted into [Resource]s.
    */
   final ResourceProvider resourceProvider;
 
   /**
    * The [Index] for this server, may be `null` if indexing is disabled.
    */
   final Index index;
@@ skipping 227 matching lines @@
       PubPackageMapProvider packageMapProvider,
       this.index,
       this.serverPlugin,
       this.options,
       this.sdkManager,
       this.instrumentationService,
       {this.diagnosticServer,
       ResolverProvider fileResolverProvider: null,
       ResolverProvider packageResolverProvider: null,
       bool useSingleContextManager: false,
-      this.rethrowExceptions: true}) {
+      this.rethrowExceptions: true})
+      // TODO(brianwilkerson) Initialize notificationManager to
+      // "new NotificationManager(channel, resourceProvider)"
+      : notificationManager = null {
     _performance = performanceDuringStartup;
     defaultContextOptions.incremental = true;
     defaultContextOptions.incrementalApi =
         options.enableIncrementalResolutionApi;
     defaultContextOptions.incrementalValidation =
         options.enableIncrementalResolutionValidation;
     defaultContextOptions.finerGrainedInvalidation =
         options.finerGrainedInvalidation;
     defaultContextOptions.generateImplicitErrors = false;
     operationQueue = new ServerOperationQueue();
@@ skipping 840 matching lines @@
    *
    * The current implementation is intentionally simplified and expected
    * that only folders are given each given folder corresponds to the exactly
    * one context.
    *
    * So, we can start working in parallel on adding services and improving
    * projects/contexts support.
    */
   void setAnalysisRoots(String requestId, List<String> includedPaths,
       List<String> excludedPaths, Map<String, String> packageRoots) {
+    if (notificationManager != null) {
+      notificationManager.setAnalysisRoots(includedPaths, excludedPaths);
+    }
     try {
       contextManager.setRoots(includedPaths, excludedPaths, packageRoots);
     } on UnimplementedError catch (e) {
       throw new RequestFailure(
           new Response.unsupportedFeature(requestId, e.message));
     }
   }
 
   /**
    * Implementation for `analysis.setSubscriptions`.
    */
   void setAnalysisSubscriptions(
       Map<AnalysisService, Set<String>> subscriptions) {
+    if (notificationManager != null) {
+      notificationManager.setSubscriptions(subscriptions);
+    }
     if (options.enableNewAnalysisDriver) {
       this.analysisServices = subscriptions;
       Iterable<nd.AnalysisDriver> drivers = driverMap.values;
       if (drivers.isNotEmpty) {
         Set<String> allNewFiles =
             subscriptions.values.expand((files) => files).toSet();
         for (String file in allNewFiles) {
           nd.AnalysisDriver driver = drivers.firstWhere(
               (driver) => driver.addedFiles.contains(file),
               orElse: () => drivers.first);
@@ skipping 996 matching lines @@
   /**
    * The [PerformanceTag] for time spent in server request handlers.
    */
   static PerformanceTag serverRequests = new PerformanceTag('serverRequests');
 
   /**
    * The [PerformanceTag] for time spent in split store microtasks.
    */
   static PerformanceTag splitStore = new PerformanceTag('splitStore');
 }