Update timer and adjust frequency.

Update timer and adjust frequency.

BUG= http://dartbug.com/19435
BUG= http://dartbug.com/19082
R=lrn@google.com

Committed: https://code.google.com/p/dart/source/detail?r=37586

[Lasse Reichstein Nielsen, 2014-06-20 12:04:02]

lgtm

https://codereview.chromium.org/345873003/diff/20001/sdk/lib/_internal/lib/js...
File sdk/lib/_internal/lib/js_helper.dart (right):

https://codereview.chromium.org/345873003/diff/20001/sdk/lib/_internal/lib/js...
sdk/lib/_internal/lib/js_helper.dart:709: return _highResolutionTimer != null ?
1000000 : 1000;
Do you need to look up the "performance" every time, or could you cache
"performance.now" the result the first time it's accessed?
Then you could also set the timerFrequency the first time it's needed.

I.e.,

  static Function timerTicks;
  static int timerFrequency;

  void _initTicker() {  // Called from Stopwatch constructor.
    if (timerTicks != null) return;
    var highPerf = _highResolutionTimer;
    if (highPerf != null) {
      timerTicks = JS("Function", "#.now", highPerf);  // Or return .now.
      timerFrequency = 1000000;
    } else {
      timerTicks = dateNow;
      timerFrequency = 1000;
    }
  }

[floitsch, 2014-06-20 22:07:20]

PTAL.

https://codereview.chromium.org/345873003/diff/20001/sdk/lib/_internal/lib/js...
File sdk/lib/_internal/lib/js_helper.dart (right):

https://codereview.chromium.org/345873003/diff/20001/sdk/lib/_internal/lib/js...
sdk/lib/_internal/lib/js_helper.dart:709: return _highResolutionTimer != null ?
1000000 : 1000;
On 2014/06/20 12:04:02, Lasse Reichstein Nielsen wrote:
> Do you need to look up the "performance" every time, or could you cache
> "performance.now" the result the first time it's accessed?
> Then you could also set the timerFrequency the first time it's needed.
> 
> I.e.,
> 
>   static Function timerTicks;
>   static int timerFrequency;
> 
>   void _initTicker() {  // Called from Stopwatch constructor.
>     if (timerTicks != null) return;
>     var highPerf = _highResolutionTimer;
>     if (highPerf != null) {
>       timerTicks = JS("Function", "#.now", highPerf);  // Or return .now.
>       timerFrequency = 1000000;
>     } else {
>       timerTicks = dateNow;
>       timerFrequency = 1000;
>     }
>   }
> 

done.

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

lgtm

https://codereview.chromium.org/345873003/diff/40001/sdk/lib/core/stopwatch.dart
File sdk/lib/core/stopwatch.dart (right):

https://codereview.chromium.org/345873003/diff/40001/sdk/lib/core/stopwatch.d...
sdk/lib/core/stopwatch.dart:14: int get frequency => _frequency;
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]

https://codereview.chromium.org/345873003/diff/40001/sdk/lib/core/stopwatch.dart
File sdk/lib/core/stopwatch.dart (right):

https://codereview.chromium.org/345873003/diff/40001/sdk/lib/core/stopwatch.d...
sdk/lib/core/stopwatch.dart:14: int get frequency => _frequency;
On 2014/06/20 23:29:52, Lasse Reichstein Nielsen wrote:
> 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.

_frequency is a static field.

[floitsch, 2014-06-23 09:35:45]

Committed patchset #3 manually as r37586 (presubmit successful).