Clamp resolution of requestIdleCallback timeRemaining() to 5us.

Clamp resolution of requestIdleCallback timeRemaining() to 5us.

BUG=532260, 514651
Committed: https://crrev.com/a732b113dd01d00aca7376b61ac20a6126cee3de
Cr-Commit-Position: refs/heads/master@{#350809}

[rmcilroy, 2015-09-24 21:30:01]

The CQ bit was checked by rmcilroy@chromium.org to run a CQ dry run

[rmcilroy, 2015-09-24 21:30:32]

rmcilroy@chromium.org changed reviewers:
+ esprehn@chromium.org

[rmcilroy, 2015-09-24 21:30:33]

Elliott, could you take a look please? Thanks.

[commit-bot: I haz the power, 2015-09-24 21:32:45]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1361803003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1361803003/1

[esprehn, 2015-09-24 21:33:06]

https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/dom/IdleDeadline.cpp (right):

https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/dom/IdleDeadline.cpp:24: const double
resolutionSeconds = 0.000005;
This is just duplicating what performance.now does, can we just call whatever
that calls? All timers in the engine should probably clamp to this...

[commit-bot: I haz the power, 2015-09-24 21:48:21]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-24 21:48:22]

Dry run: Try jobs failed on following builders:
  mac_chromium_gn_rel on tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_gn_r...)

[rmcilroy, 2015-09-24 22:53:18]

rmcilroy@chromium.org changed reviewers:
+ igrigorik@chromium.org

[rmcilroy, 2015-09-24 22:53:18]

https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/dom/IdleDeadline.cpp (right):

https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/dom/IdleDeadline.cpp:24: const double
resolutionSeconds = 0.000005;
On 2015/09/24 21:33:06, esprehn wrote:
> This is just duplicating what performance.now does, can we just call whatever
> that calls?

Good idea, added PerformanceBase::clampTimeResolution for this (happy to move
this if you have a suggestion for a better location).

> All timers in the engine should probably clamp to this...

By this do you mean the likes of PerformanceTimer, PerformanceUserTiming,
ResourceTimingInfo, etc? Ilya: would this work from a spec point of view? If so
I can do this in a followup CL.

[rmcilroy, 2015-09-24 22:54:07]

The CQ bit was checked by rmcilroy@chromium.org to run a CQ dry run

[esprehn, 2015-09-24 22:54:39]

On 2015/09/24 at 22:53:18, rmcilroy wrote:
>
https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
> File third_party/WebKit/Source/core/dom/IdleDeadline.cpp (right):
> 
>
https://codereview.chromium.org/1361803003/diff/1/third_party/WebKit/Source/c...
> third_party/WebKit/Source/core/dom/IdleDeadline.cpp:24: const double
resolutionSeconds = 0.000005;
> On 2015/09/24 21:33:06, esprehn wrote:
> > This is just duplicating what performance.now does, can we just call
whatever
> > that calls?
> 
> Good idea, added PerformanceBase::clampTimeResolution for this (happy to move
this if you have a suggestion for a better location).
> 
> > All timers in the engine should probably clamp to this...
> 
> By this do you mean the likes of PerformanceTimer, PerformanceUserTiming,
ResourceTimingInfo, etc? Ilya: would this work from a spec point of view? If so
I can do this in a followup CL.

Yes, the whole platform should provide a uniform timing view. Everything should
clamp to 5us all over. :)

[commit-bot: I haz the power, 2015-09-24 22:54:46]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1361803003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1361803003/20001

[commit-bot: I haz the power, 2015-09-24 23:02:01]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-09-24 23:02:01]

Dry run: Try jobs failed on following builders:
  win8_chromium_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win8_chromium_ng/...)
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[rmcilroy, 2015-09-24 23:16:09]

> > By this do you mean the likes of PerformanceTimer, PerformanceUserTiming,
> ResourceTimingInfo, etc? Ilya: would this work from a spec point of view? If
so
> I can do this in a followup CL.
> 
> Yes, the whole platform should provide a uniform timing view. Everything
should
> clamp to 5us all over. :)

OK. I'd still like to do the other platform APIs as a separate CL to ensure it
can be reverted / relanded if it causes problems with tests. 

If you are fine with the approach I've taken with this CL could we land it first
then I'll followup with the others?

[esprehn, 2015-09-24 23:27:30]

lgtm

[esprehn, 2015-09-24 23:27:37]

On 2015/09/24 at 23:27:30, esprehn wrote:
> lgtm

Should we move the * 1000 in there too?

[igrigorik, 2015-09-24 23:46:15]

On 2015/09/24 22:54:39, esprehn wrote:
> On 2015/09/24 at 22:53:18, rmcilroy wrote:
> > By this do you mean the likes of PerformanceTimer, PerformanceUserTiming,
> ResourceTimingInfo, etc? Ilya: would this work from a spec point of view? If
so
> I can do this in a followup CL.
> 
> Yes, the whole platform should provide a uniform timing view. Everything
should
> clamp to 5us all over. :)

Yep. The 5us clamp is part of HR-Time, so it should apply uniformly to all
DOMHighResTimestamp's.

[rmcilroy, 2015-09-25 10:18:58]

On 2015/09/24 23:27:37, esprehn wrote:
> On 2015/09/24 at 23:27:30, esprehn wrote:
> > lgtm
> 
> Should we move the * 1000 in there too?

I thought of that, but decided against it because I thought it would be too
confusing to have a method which both clamped and scaled the time.

[rmcilroy, 2015-09-25 10:20:38]

The CQ bit was checked by rmcilroy@chromium.org

[rmcilroy, 2015-09-25 10:20:38]

The patchset sent to the CQ was uploaded after l-g-t-m from esprehn@chromium.org
Link to the patchset: https://codereview.chromium.org/1361803003/#ps40001
(title: "Rebase")

[commit-bot: I haz the power, 2015-09-25 10:20:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1361803003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1361803003/40001

[commit-bot: I haz the power, 2015-09-25 12:38:12]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-09-25 12:39:12]

Patchset 3 (id:??) landed as
https://crrev.com/a732b113dd01d00aca7376b61ac20a6126cee3de
Cr-Commit-Position: refs/heads/master@{#350809}