Update charted to 0.4.8 and roll

packages/observe/benchmark/setup_observation_benchmark_base.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 observe.test.benchmark.setup_observation_benchmark_base;
-
-import 'dart:async';
-import 'dart:html';
-import 'package:observe/observe.dart';
-import 'package:benchmark_harness/benchmark_harness.dart';
-
-abstract class SetupObservationBenchmarkBase extends BenchmarkBase {
-  /// The number of objects to create and observe.
-  final int objectCount;
-
-  /// The current configuration.
-  final String config;
-
-  /// The objects we want to observe.
-  List<Observable> objects;
-
-  SetupObservationBenchmarkBase(String name, this.objectCount, this.config)
-      : super(name);
-
-  /// Subclasses should use this method to return an observable object to be
-  /// benchmarked.
-  Observable newObject();
-
-  /// Subclasses should override this to do anything other than a default change
-  /// listener. It must return either a StreamSubscription or a PathObserver.
-  newObserver(obj) => obj.changes.listen((_) {});
-
-  /// Set up each benchmark by creating all the objects.
-  @override
-  void setup() {
-    objects = [];
-    while (objects.length < objectCount) {
-      objects.add(newObject());
-    }
-  }
-
-  /// Tear down each the benchmark and remove all listeners.
-  @override
-  void teardown() {
-    while (objects.isNotEmpty) {
-      var obj = objects.removeLast();
-      if (obj.hasObservers || (obj is ObservableList && obj.hasListObservers)) {
-        window.alert('Observers leaked!');
-      }
-    }
-    objects = null;
-  }
-
-  /// Run the benchmark by creating a listener on each object.
-  @override
-  void run() {
-    for (var object in objects) {
-      var observer = newObserver(object);
-
-      // **Note:** This is different than the JS implementation. Since run can
-      // be called an arbitrary number of times between [setup] and [teardown],
-      // we clean up all observers as we go. This means we are measuring both
-      // the setup and teardown of observers, versus the setup only in the
-      // JS benchmark. Not cleaning these up ends up giving `oh snap` errors.
-      if (observer is StreamSubscription) {
-        observer.cancel();
-      } else if (observer is PathObserver) {
-        observer.close();
-      } else {
-        throw 'Unknown observer type ${observer.runtimeType}. Only '
-            '[PathObserver] and [StreamSubscription] are supported.';
-      }
-    }
-  }
-}