Roll Observatory packages and add a roll script

packages/barback/test/transformer/bad_log.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 barback.test.transformer.bad_log;
+
+import 'package:barback/barback.dart';
+
+import 'mock.dart';
+
+/// A transformer that logs an error when run, Before generating the given
+/// outputs.
+class BadLogTransformer extends MockTransformer {
+  /// The list of asset names that it should output.
+  final List<String> outputs;
+
+  BadLogTransformer(this.outputs);
+
+  bool doIsPrimary(AssetId id) => true;
+
+  void doApply(Transform transform) {
+    transform.logger.error("first error");
+    transform.logger.error("second error");
+
+    for (var output in outputs) {
+      var id = new AssetId.parse(output);
+      transform.addOutput(new Asset.fromString(id, output));
+    }
+  }
+}