Add additional PageLoad UKM metrics using new UKM client API.

Add additional PageLoad UKM metrics using new UKM client API.

This change adds core PageLoad metrics to UKM. The new metrics are:
* first meaningful paint (experimental)
* foreground duration
* parse start
* dom content loaded
* load event

BUG=697454
Review-Url: https://codereview.chromium.org/2727143004
Cr-Commit-Position: refs/heads/master@{#454308}
Committed: https://chromium.googlesource.com/chromium/src/+/8c68311a3f7c731ecf774e4ac411bbd2179436fb

[Bryan McQuade, 2017-03-02 13:55:23]

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

[commit-bot: I haz the power, 2017-03-02 13:55:38]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Bryan McQuade, 2017-03-02 13:59:50]

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

[commit-bot: I haz the power, 2017-03-02 14:00:10]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Bryan McQuade, 2017-03-02 14:07:51]

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

[commit-bot: I haz the power, 2017-03-02 14:08:08]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-02 15:04:48]

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

[commit-bot: I haz the power, 2017-03-02 15:04:48]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[Bryan McQuade, 2017-03-02 16:20:39]

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

[commit-bot: I haz the power, 2017-03-02 16:20:58]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Bryan McQuade, 2017-03-02 16:21:38]

bmcquade@chromium.org changed reviewers:
+ rkaplow@chromium.org

[Bryan McQuade, 2017-03-02 16:21:45]

rkaplow, PTAL, thanks!

[commit-bot: I haz the power, 2017-03-02 17:02:09]

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

[commit-bot: I haz the power, 2017-03-02 17:02:10]

Dry run: This issue passed the CQ dry run.

[Bryan McQuade, 2017-03-02 17:37:39]

bmcquade@chromium.org changed reviewers:
+ zhenw@chromium.org

[Bryan McQuade, 2017-03-02 17:43:51]

zhenw and rkaplow, PTAL, thanks!

[Zhen Wang, 2017-03-02 17:58:21]

lgtm

[Bryan McQuade, 2017-03-02 18:02:33]

The CQ bit was checked by bmcquade@chromium.org

[commit-bot: I haz the power, 2017-03-02 18:03:03]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[tdresser, 2017-03-02 18:06:00]

tdresser@chromium.org changed reviewers:
+ tdresser@chromium.org

[tdresser, 2017-03-02 18:06:01]

https://codereview.chromium.org/2727143004/diff/60001/chrome/browser/page_loa...
File
chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.cc
(right):

https://codereview.chromium.org/2727143004/diff/60001/chrome/browser/page_loa...
chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.cc:22:
const char kUkmForegroundDurationName[] = "PageTiming.ForegroundDuration";
All of DocumentTiming, PageTiming, PaintTiming and ParseTiming feel like they
perhaps belong under a common "LoadTiming" prefix. I guess we're just trying to
match the UMA names here?

Is that going to be general practice with UKM?

(I don't have strong opinions either way, but we should probably be consistent)

[commit-bot: I haz the power, 2017-03-02 18:13:00]

CQ is committing da patch.

Bot data: {"patchset_id": 60001, "attempt_start_ts": 1488477753377680,
"parent_rev": "76004798b3237c002bd84d5bfb6ff524d9ebb248", "commit_rev":
"8c68311a3f7c731ecf774e4ac411bbd2179436fb"}

[commit-bot: I haz the power, 2017-03-02 18:13:59]

Description was changed from

==========
Add additional PageLoad UKM metrics using new UKM client API.

This change adds core PageLoad metrics to UKM. The new metrics are:
* first meaningful paint (experimental)
* foreground duration
* parse start
* dom content loaded
* load event

BUG=697454
==========

to

==========
Add additional PageLoad UKM metrics using new UKM client API.

This change adds core PageLoad metrics to UKM. The new metrics are:
* first meaningful paint (experimental)
* foreground duration
* parse start
* dom content loaded
* load event

BUG=697454

Review-Url: https://codereview.chromium.org/2727143004
Cr-Commit-Position: refs/heads/master@{#454308}
Committed:
https://chromium.googlesource.com/chromium/src/+/8c68311a3f7c731ecf774e4ac411...
==========

[commit-bot: I haz the power, 2017-03-02 18:14:00]

Committed patchset #4 (id:60001) as
https://chromium.googlesource.com/chromium/src/+/8c68311a3f7c731ecf774e4ac411...

[Bryan McQuade, 2017-03-02 18:16:53]

On 2017/03/02 at 18:06:01, tdresser wrote:
>
https://codereview.chromium.org/2727143004/diff/60001/chrome/browser/page_loa...
> File
chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.cc
(right):
> 
>
https://codereview.chromium.org/2727143004/diff/60001/chrome/browser/page_loa...
>
chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.cc:22:
const char kUkmForegroundDurationName[] = "PageTiming.ForegroundDuration";
> All of DocumentTiming, PageTiming, PaintTiming and ParseTiming feel like they
perhaps belong under a common "LoadTiming" prefix. I guess we're just trying to
match the UMA names here?
> 
> Is that going to be general practice with UKM?
> 
> (I don't have strong opinions either way, but we should probably be
consistent)

Yeah, all of these are grouped under the 'PageLoad' UKM event name. For now,
we're re-using the same names as UMA so we can reason about them more easily
when looking at UMA data and UKM data (same name = same metric across the 2
systems). But it may be the case that we should rename. It's probably worth
reviewing all the existing UMA names to see if there's anything that should
change there, and then maybe we update both at once.