Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some slow fetch() requests in the test page.

BUG=651870
Review-Url: https://codereview.chromium.org/2799423002
Cr-Commit-Position: refs/heads/master@{#463165}
Committed: https://chromium.googlesource.com/chromium/src/+/115a1494e75fec1c214329b8e8f0be9b35194785

[Kunihiko Sakamoto, 2017-04-07 07:32:54]

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

[commit-bot: I haz the power, 2017-04-07 07:33:14]

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

[Kunihiko Sakamoto, 2017-04-07 08:08:19]

Description was changed from

==========
Attempt to deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

BUG=651870
==========

to

==========
Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some network requests in the test page.

BUG=651870
==========

[Kunihiko Sakamoto, 2017-04-07 08:09:59]

Description was changed from

==========
Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some network requests in the test page.

BUG=651870
==========

to

==========
Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some slow fetch() requests in the test page.

BUG=651870
==========

[Kunihiko Sakamoto, 2017-04-07 08:40:39]

ksakamoto@chromium.org changed reviewers:
+ bmcquade@chromium.org, csharrison@chromium.org

[commit-bot: I haz the power, 2017-04-07 09:24:20]

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

[commit-bot: I haz the power, 2017-04-07 09:24:21]

Dry run: This issue passed the CQ dry run.

[Charlie Harrison, 2017-04-07 13:39:56]

LGTM

[Kunihiko Sakamoto, 2017-04-10 01:09:49]

The CQ bit was checked by ksakamoto@chromium.org

[commit-bot: I haz the power, 2017-04-10 01:09:57]

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, 2017-04-10 02:13:19]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1491786589368560, "parent_rev":
"93b8c34db71156846a5c60d71b8ae447cbd5165a", "commit_rev":
"115a1494e75fec1c214329b8e8f0be9b35194785"}

[commit-bot: I haz the power, 2017-04-10 02:14:08]

Description was changed from

==========
Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some slow fetch() requests in the test page.

BUG=651870
==========

to

==========
Deflake PageLoadMetricsBrowserTest.FirstMeaningfulPaintNotRecorded

There are two causes of flakiness:

1. ui_test_utils::NavigateToURL() does not guarantee that the page had
   a paint after the navigation. FirstMeaningfulPaintStatus will not be
   logged if the page is not painted at all. This patch adds a FCP
   observer to prevent this.

2. The page may reach network-idle and report FirstMeaningfulPaint
   before the tester calls NavigateToUntrackedUrl(). To prevent this,
   this patch adds some slow fetch() requests in the test page.

BUG=651870

Review-Url: https://codereview.chromium.org/2799423002
Cr-Commit-Position: refs/heads/master@{#463165}
Committed:
https://chromium.googlesource.com/chromium/src/+/115a1494e75fec1c214329b8e8f0...
==========

[commit-bot: I haz the power, 2017-04-10 02:14:09]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/115a1494e75fec1c214329b8e8f0...