Fix bugs where events could be added after watchers were closed.

lib/src/directory_watcher/linux.dart

 // Copyright (c) 2013, 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 watcher.directory_watcher.linux;
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:stack_trace/stack_trace.dart';
@@ skipping 116 matching lines @@
     var watcher = new _LinuxDirectoryWatcher(path);
     _subWatchers[path] = watcher;
 
     // TODO(nweiz): Catch any errors here that indicate that the directory in
     // question doesn't exist and silently stop watching it instead of
     // propagating the errors.
     _listen(watcher.events, (event) {
       if (isReady) _eventsController.add(event);
     }, onError: (error, stackTrace) {
       _eventsController.addError(error, stackTrace);
-      _eventsController.close();
+      close();
     }, onDone: () {
       if (_subWatchers[path] == watcher) _subWatchers.remove(path);
 
       // It's possible that a directory was removed and recreated very quickly.
       // If so, make sure we're still watching it.
       if (new Directory(path).existsSync()) _watchSubdir(path);
     });
 
     // TODO(nweiz): Right now it's possible for the watcher to emit an event for
     // a file before the directory list is complete. This could lead to the user
@@ skipping 151 matching lines @@
   static const DIRECTORY = const _EntryState._("directory");
 
   const _EntryState._(this._name);
 
   /// Returns [DIRECTORY] if [isDir] is true, and [FILE] otherwise.
   factory _EntryState(bool isDir) =>
       isDir ? _EntryState.DIRECTORY : _EntryState.FILE;
 
   String toString() => _name;
 }