Add Resource.delete() method.

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 analyzer.file_system.file_system;
 
 import 'dart:async';
 
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/util/absolute_path.dart';
@@ skipping 137 matching lines @@
    */
   String get path;
 
   /**
    * Return a short version of the name that can be displayed to the user to
    * denote this resource.
    */
   String get shortName;
 
   /**
+   * Synchronously deletes this resource and its children.
+   *
+   * Throws an exception if the resource cannot be deleted.
+   */
+  void delete();
+
+  /**
    * 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.
  */
@@ skipping 65 matching lines @@
 
   @override
   Uri restoreAbsolute(Source source) =>
       _provider.pathContext.toUri(source.fullName);
 
   /**
    * Return `true` if the given [uri] is a `file` URI.
    */
   static bool _isFileUri(Uri uri) => uri.scheme == _FILE_SCHEME;
 }