Remove barback from the repo.

pkg/barback/test/cancelable_future_test.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 barback.test.cancelable_future_test;
-
-import 'dart:async';
-
-import 'package:barback/src/utils.dart';
-import 'package:barback/src/utils/cancelable_future.dart';
-import 'package:unittest/unittest.dart';
-
-import 'utils.dart';
-
-main() {
-  initConfig();
-
-  var completer;
-  var future;
-  setUp(() {
-    completer = new Completer();
-    future = new CancelableFuture(completer.future);
-  });
-
-  group("when not canceled", () {
-    test("correctly completes successfully", () {
-      expect(future, completion(equals("success")));
-      completer.complete("success");
-    });
-
-    test("correctly completes with an error", () {
-      expect(future, throwsA(equals("error")));
-      completer.completeError("error");
-    });
-  });
-
-  group("when canceled", () {
-    test("never completes successfully", () {
-      var completed = false;
-      future.whenComplete(() {
-        completed = true;
-      });
-
-      future.cancel();
-      completer.complete("success");
-
-      expect(pumpEventQueue().then((_) => completed), completion(isFalse));
-    });
-
-    test("never completes with an error", () {
-      var completed = false;
-      future.catchError((_) {}).whenComplete(() {
-        completed = true;
-      });
-
-      future.cancel();
-      completer.completeError("error");
-
-      expect(pumpEventQueue().then((_) => completed), completion(isFalse));
-    });
-  });
-}