Roll Observatory packages and add a roll script

packages/observe/benchmark/observation_benchmark_base.dart

Index: packages/observe/benchmark/observation_benchmark_base.dart
diff --git a/packages/observe/benchmark/observation_benchmark_base.dart b/packages/observe/benchmark/observation_benchmark_base.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c087f57060774f2964aa3433c778bd29643e80cf
--- /dev/null
+++ b/packages/observe/benchmark/observation_benchmark_base.dart
@@ -0,0 +1,117 @@
+// 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.observation_benchmark_base;
+
+import 'dart:async';
+import 'dart:html';
+import 'package:observe/observe.dart';
+import 'package:benchmark_harness/benchmark_harness.dart';
+
+abstract class ObservationBenchmarkBase extends BenchmarkBase {
+  /// The number of objects to create and observe.
+  final int objectCount;
+
+  /// The number of mutations to perform.
+  final int mutationCount;
+
+  /// The current configuration.
+  final String config;
+
+  /// The number of pending mutations left to observe.
+  int mutations;
+
+  /// The objects we want to observe.
+  List<Observable> objects;
+
+  /// The change listeners on all of our objects.
+  List observers;
+
+  /// The current object being mutated.
+  int objectIndex;
+
+  ObservationBenchmarkBase(
+      String name, this.objectCount, this.mutationCount, this.config)
+      : super(name);
+
+  /// Subclasses should use this method to perform mutations on an object. The
+  /// return value indicates how many mutations were performed on the object.
+  int mutateObject(obj);
+
+  /// 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.
+  /// If overridden this observer should decrement [mutations] each time a
+  /// change is observed.
+  newObserver(obj) {
+    decrement(_) => mutations--;
+    if (obj is ObservableList) return obj.listChanges.listen(decrement);
+    return obj.changes.listen(decrement);
+  }
+
+  /// Set up each benchmark by creating all the objects and listeners.
+  @override
+  void setup() {
+    mutations = 0;
+
+    objects = [];
+    observers = [];
+    objectIndex = 0;
+
+    while (objects.length < objectCount) {
+      var obj = newObject();
+      objects.add(obj);
+      observers.add(newObserver(obj));
+    }
+  }
+
+  /// Tear down each benchmark and make sure that [mutations] is 0.
+  @override
+  void teardown() {
+    if (mutations != 0) {
+      window.alert('$mutations mutation sets were not observed!');
+    }
+    mutations = 0;
+
+    while (observers.isNotEmpty) {
+      var observer = observers.removeLast();
+      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.';
+      }
+    }
+    observers = null;
+
+    bool leakedObservers = false;
+    while (objects.isNotEmpty) {
+      leakedObservers = objects.removeLast().hasObservers || leakedObservers;
+    }
+    if (leakedObservers) window.alert('Observers leaked!');
+    objects = null;
+  }
+
+  /// Run the benchmark
+  @override
+  void run() {
+    var mutationsLeft = mutationCount;
+    while (mutationsLeft > 0) {
+      var obj = objects[objectIndex];
+      mutationsLeft -= mutateObject(obj);
+      this.mutations++;
+      this.objectIndex++;
+      if (this.objectIndex == this.objects.length) {
+        this.objectIndex = 0;
+      }
+      obj.deliverChanges();
+      if (obj is ObservableList) obj.deliverListChanges();
+    }
+    Observable.dirtyCheck();
+  }
+}