Update the Mac OS watcher in pkg/watcher.

pkg/watcher/test/no_subscription/shared.dart

 // Copyright (c) 2012, 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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:scheduled_test/scheduled_test.dart';
 import 'package:watcher/watcher.dart';
 
@@ skipping 23 matching lines @@
       subscription.cancel();
     });
 
     // Now write a file while we aren't listening.
     writeFile("unwatched.txt");
 
     // Then start listening again.
     schedule(() {
       completer = new Completer();
       subscription = watcher.events.listen(wrapAsync((event) {
-        // TODO(nweiz): Remove this when either issue 14373 or 14793 is fixed.
-        // Issue 14373 means that the new [Directory.watch] will emit an event
-        // for "unwatched.txt" being created, and issue 14793 means we have to
-        // check the filesystem, which leads us to assume that the file has been
-        // modified.
-        if (Platform.isMacOS && event.path.endsWith("unwatched.txt")) {
-          expect(event, isWatchEvent(ChangeType.MODIFY, "unwatched.txt"));
-          return;
-        }
-
         // We should get an event for the third file, not the one added while
         // we weren't subscribed.
         expect(event, isWatchEvent(ChangeType.ADD, "added.txt"));
         completer.complete();
       }));
 
       // Wait until the watcher is ready to dispatch events again.
       return watcher.ready;
     });
 
     // And add a third file.
     writeFile("added.txt");
 
     // Wait until we get an event for the third file.
     schedule(() => completer.future);
 
     schedule(() {
       subscription.cancel();
     });
   });
 }