Support for excluded files/folders.

pkg/analyzer/lib/file_system/file_system.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 file_system;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/source.dart';
 import 'package:path/path.dart';
@@ skipping 68 matching lines @@
   /**
    * Return the full path to this resource.
    */
   String get path;
 
   /**
    * Return a short version of the name that can be displayed to the user to
    * denote this resource.
    */
   String get shortName;
+
+  /**
+   * Return `true` if absolute [path] references this resource or a resource in
+   * this folder.
+   */
+  bool isOrContains(String path);
 }
 
 
 /**
  * Instances of the class [ResourceProvider] convert [String] paths into
  * [Resource]s.
  */
 abstract class ResourceProvider {
   /**
    * Get the path context used by this resource provider.
@@ skipping 33 matching lines @@
   }
 
   /**
    * Return `true` if the given URI is a `file` URI.
    *
    * @param uri the URI being tested
    * @return `true` if the given URI is a `file` URI
    */
   static bool _isFileUri(Uri uri) => uri.scheme == _FILE_SCHEME;
 }