Update charted to 0.4.8 and roll

packages/quiver/lib/src/async/countdown_timer.dart

 // Copyright 2013 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 part of quiver.async;
 
-/**
- * A simple countdown timer that fires events in regular increments until a
- * duration has passed.
- *
- * CountdownTimer implements [Stream] and sends itself as the event. From the
- * timer you can get the [remaining] and [elapsed] time, or [cancel] the timer.
- */
+/// A simple countdown timer that fires events in regular increments until a
+/// duration has passed.
+///
+/// CountdownTimer implements [Stream] and sends itself as the event. From the
+/// timer you can get the [remaining] and [elapsed] time, or [cancel] the
+/// timer.
 class CountdownTimer extends Stream<CountdownTimer> {
   static const _THRESHOLD_MS = 4;
 
   final Duration _duration;
-  final Duration _increment;
   final Stopwatch _stopwatch;
+
+  /// The duration between timer events.
+  final Duration increment;
   final StreamController<CountdownTimer> _controller;
   Timer _timer;
 
-  /**
-   * Creates a new [CountdownTimer] that fires events in increments of
-   * [increment], until the [duration] has passed.
-   *
-   * [stopwatch] is for testing purposes. If you're using CountdownTimer and
-   * need to control time in a test, pass a mock or a fake. See [FakeAsync] and
-   * [FakeStopwatch].
-   */
+  /// Creates a new [CountdownTimer] that fires events in increments of
+  /// [increment], until the [duration] has passed.
+  ///
+  /// [stopwatch] is for testing purposes. If you're using CountdownTimer and
+  /// need to control time in a test, pass a mock or a fake. See [FakeAsync]
+  /// and [FakeStopwatch].
   CountdownTimer(Duration duration, Duration increment, {Stopwatch stopwatch})
       : _duration = duration,
-        _increment = increment,
+        increment = increment,
         _stopwatch = stopwatch == null ? new Stopwatch() : stopwatch,
-        _controller = new StreamController<CountdownTimer>.broadcast(
-            sync: true) {
+        _controller =
+            new StreamController<CountdownTimer>.broadcast(sync: true) {
     _timer = new Timer.periodic(increment, _tick);
     _stopwatch.start();
   }
 
   StreamSubscription<CountdownTimer> listen(void onData(CountdownTimer event),
           {Function onError, void onDone(), bool cancelOnError}) =>
       _controller.stream.listen(onData, onError: onError, onDone: onDone);
 
   Duration get elapsed => _stopwatch.elapsed;
 
   Duration get remaining => _duration - _stopwatch.elapsed;
 
   bool get isRunning => _stopwatch.isRunning;
 
   cancel() {
     _stopwatch.stop();
     _timer.cancel();
     _controller.close();
   }
 
   _tick(Timer timer) {
     var t = remaining;
     _controller.add(this);
     // timers may have a 4ms resolution
     if (t.inMilliseconds < _THRESHOLD_MS) {
       cancel();
     }
   }
 }