Update charted to 0.4.8 and roll

packages/quiver/lib/testing/src/time/time.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.testing.time;
 
-/**
- * Returns the current test time in microseconds.
- */
+/// Returns the current test time in microseconds.
 typedef int Now();
 
-/**
- * A [Stopwatch] implementation that gets the current time in microseconds
- * via a user-supplied function.
- */
+/// A [Stopwatch] implementation that gets the current time in microseconds
+/// via a user-supplied function.
 class FakeStopwatch implements Stopwatch {
   Now _now;
   int frequency;
   int _start;
   int _stop;
 
   FakeStopwatch(int now(), int this.frequency)
       : _now = now,
         _start = null,
         _stop = null;
@@ skipping 29 matching lines @@
   }
 
   Duration get elapsed => new Duration(microseconds: elapsedMicroseconds);
 
   int get elapsedMicroseconds => (elapsedTicks * 1000000) ~/ frequency;
 
   int get elapsedMilliseconds => (elapsedTicks * 1000) ~/ frequency;
 
   bool get isRunning => _start != null && _stop == null;
 }