Roll Observatory packages and add a roll script

code_transformers/lib/benchmarks.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 code_transformers.benchmarks;
-
-import 'dart:async';
-import 'package:barback/barback.dart';
-import 'src/async_benchmark_base.dart';
-
-/// A benchmark for testing the performance of transformer phases.
-class TransformerBenchmark extends AsyncBenchmarkBase {
-  /// Internal abstraction layer for barback.
-  _BenchmarkHelper _helper;
-
-  /// The transformer phases to be ran.
-  final List<List<Transformer>> transformers;
-
-  /// The files to pass to barback.
-  final Map<AssetId, String> files;
-
-  TransformerBenchmark(this.transformers, this.files);
-
-  @override
-  Future setup() {
-    _helper = new _BenchmarkHelper(transformers, files);
-    return new Future.value();
-  }
-
-  @override
-  Future run() => _helper.run();
-
-  @override
-  teardown() {
-    _helper = null;
-    return new Future.value();
-  }
-}
-
-/// Barback abstraction layer.
-class _BenchmarkHelper implements PackageProvider {
-  /// All the files available.
-  final Map<AssetId, String> _files;
-
-  /// All the packages.
-  final Iterable<String> packages;
-
-  /// Internal instance of barback.
-  Barback _barback;
-
-  /// Subscription to barback results.
-  StreamSubscription<BuildResult> resultSubscription;
-
-  _BenchmarkHelper(
-      List<List<Transformer>> transformers, Map<AssetId, String> files)
-      : _files = files,
-        packages = new Set.from(files.keys.map((assetId) => assetId.package)) {
-    _barback = new Barback(this);
-    for (var package in packages) {
-      _barback.updateTransformers(package, transformers);
-    }
-  }
-
-  /// Look up an [AssetId] in [files] and return an [Asset] for it.
-  @override
-  Future<Asset> getAsset(AssetId id) =>
-      new Future.value(new Asset.fromString(id, _files[id]));
-
-  /// Tells barback which files have changed, and thus anything that depends on
-  /// it on should be computed. Returns a [Future] that completes once some
-  /// results are received.
-  Future run([Iterable<AssetId> assetIds]) {
-    if (assetIds == null) assetIds = _files.keys;
-    _barback.updateSources(assetIds);
-    return _barback.results.first;
-  }
-}