Issue 24612. Skip excluded folder during contexts creation.

pkg/analysis_server/lib/src/context_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 context.directory.manager;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:core' hide Resource;
@@ skipping 877 matching lines @@
    * created for them and excluded from the context associated with the
    * [folder].
    *
    * If [withPackageSpecOnly] is `true`, a context will be created only if there
    * is a 'pubspec.yaml' or '.packages' file in the [folder].
    *
    * [parent] should be the parent of any contexts that are created.
    */
   void _createContexts(
       ContextInfo parent, Folder folder, bool withPackageSpecOnly) {
-    if (folder.shortName.startsWith('.') || folder.shortName == 'packages') {
+    if (_isExcluded(folder.path) ||
+        folder.shortName.startsWith('.') ||
+        folder.shortName == 'packages') {
       return;
     }
     // Decide whether a context needs to be created for [folder] here, and if
     // so, create it.
     File packageSpec = _findPackageSpecFile(folder);
     bool createContext = packageSpec.exists || !withPackageSpecOnly;
     if (withPackageSpecOnly &&
         packageSpec.exists &&
         parent != null &&
         parent.ignored(packageSpec.path)) {
@@ skipping 534 matching lines @@
           var path = resourceProvider.pathContext.fromUri(uri);
           packageMap[name] = <Folder>[resourceProvider.getFolder(path)];
         }
       });
       return <UriResolver>[new SdkExtUriResolver(packageMap)];
     } else {
       return const <UriResolver>[];
     }
   }
 }