Get rid of all the library tags.

lib/src/error_group.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 pub.error_group;
-
 import 'dart:async';
 
 /// An [ErrorGroup] entangles the errors of multiple [Future]s and [Stream]s
 /// with one another.
 ///
 /// This allows APIs to expose multiple [Future]s and [Stream]s that have
 /// identical error conditions without forcing API consumers to attach error
 /// handling to objects they don't care about.
 ///
 /// To use an [ErrorGroup], register [Future]s and [Stream]s with it using
@@ skipping 271 matching lines @@
   void _signalError(var e, [StackTrace stackTrace]) {
     if (_isDone) return;
     _subscription.cancel();
     // Call these asynchronously to work around issue 7913.
     new Future.value().then((_) {
       _controller.addError(e, stackTrace);
       _controller.close();
     });
   }
 }