Update timer and adjust frequency.

sdk/lib/core/stopwatch.dart

 // Copyright (c) 2011, 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.
 
 part of dart.core;
 
 /**
  * A simple stopwatch interface to measure elapsed time.
  */
 class Stopwatch {
   /**
    * Frequency of the elapsed counter in Hz.
    */
-  final int frequency = _frequency();
+  int get frequency => _frequency;

[Lasse Reichstein Nielsen, 2014/06/20 23:29:52]

Perhaps make this one external, so you don't need a frequency field on each
StopWatch object that all contain the same value as Primitives.tickerFrequency.

[floitsch, 2014/06/23 08:54:26]

_frequency is a static field.

 
   // The _start and _stop fields capture the time when [start] and [stop]
   // are called respectively.
   // If _start is null, then the [Stopwatch] has not been started yet.
   // If _stop is null, then the [Stopwatch] has not been stopped yet,
   // or is running.
   int _start;
   int _stop;
 
   /**
    * Creates a [Stopwatch] in stopped state with a zero elapsed count.
    *
    * The following example shows how to start a [Stopwatch]
    * immediately after allocation.
    *
    *     Stopwatch stopwatch = new Stopwatch()..start();
    */
-  Stopwatch();
+  Stopwatch() {
+    _initTicker();
+  }
 
   /**
    * Starts the [Stopwatch].
    *
    * The [elapsed] count is increasing monotonically. If the [Stopwatch] has
    * been stopped, then calling start again restarts it without resetting the
    * [elapsed] count.
    *
    * If the [Stopwatch] is currently running, then calling start does nothing.
    */
@@ skipping 77 matching lines @@
   int get elapsedMilliseconds {
     return (elapsedTicks * 1000) ~/ frequency;
   }
 
 
   /**
    * Returns wether the [StopWatch] is currently running.
    */
   bool get isRunning => _start != null && _stop == null;
 
-  external static int _frequency();
+  /**
+   * Cached frequency of the system. Must be initialized in [_initTicker];
+   */
+  static int _frequency;
+
+  /**
+   * Initializes the time-measuring system. *Must* initialize the [_frequency]
+   * variable.
+   */
+  external static void _initTicker();
   external static int _now();
 }