Increase priority of XHR in ResourcePriorities experiment.

Increase priority of XHR in ResourcePriorities experiment.

This fixes the issue where the experiment moved XHR from "not delayable"
to "delayable".  It was caught by the Service Workers micro-benchmark but
is a general issue (don't expect much real world impact but it makes more
sense to not delay XHR since it could be used for just about anything).

This change matches what we already do to script, font and CSS
priorities.

BUG=587507
Committed: https://crrev.com/1e2eb58c114b87acb269b022a9074d7290fcdbde
Cr-Commit-Position: refs/heads/master@{#380192}

[Pat Meenan, 2016-03-09 17:20:34]

pmeenan@chromium.org changed reviewers:
+ japhet@chromium.org

[Pat Meenan, 2016-03-09 17:20:35]

japhet@ PTAL.

This fixes an issue with the resource priorities experiment specific to XHR that
was exposed by the perf bots when I went to enable it by default.

[Nate Chapin, 2016-03-09 17:43:47]

LGTM, but can you add a case to 
FrameFetchContextTest.ModifyPriorityForExperiments to test this?

[Pat Meenan, 2016-03-09 18:18:30]

On 2016/03/09 17:43:47, Nate Chapin wrote:
> LGTM, but can you add a case to 
> FrameFetchContextTest.ModifyPriorityForExperiments to test this?

Done.  Thanks.

[Nate Chapin, 2016-03-09 18:23:16]

thanks, lgtm

[Pat Meenan, 2016-03-09 18:28:36]

The CQ bit was checked by pmeenan@chromium.org

[commit-bot: I haz the power, 2016-03-09 18:28:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1783433003/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1783433003/20001

[commit-bot: I haz the power, 2016-03-09 20:09:29]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-09 20:10:55]

Description was changed from

==========
Increase priority of XHR in ResourcePriorities experiment.

This fixes the issue where the experiment moved XHR from "not delayable"
to "delayable".  It was caught by the Service Workers micro-benchmark but
is a general issue (don't expect much real world impact but it makes more
sense to not delay XHR since it could be used for just about anything).

This change matches what we already do to script, font and CSS
priorities.

BUG=587507
==========

to

==========
Increase priority of XHR in ResourcePriorities experiment.

This fixes the issue where the experiment moved XHR from "not delayable"
to "delayable".  It was caught by the Service Workers micro-benchmark but
is a general issue (don't expect much real world impact but it makes more
sense to not delay XHR since it could be used for just about anything).

This change matches what we already do to script, font and CSS
priorities.

BUG=587507

Committed: https://crrev.com/1e2eb58c114b87acb269b022a9074d7290fcdbde
Cr-Commit-Position: refs/heads/master@{#380192}
==========

[commit-bot: I haz the power, 2016-03-09 20:10:56]

Patchset 2 (id:??) landed as
https://crrev.com/1e2eb58c114b87acb269b022a9074d7290fcdbde
Cr-Commit-Position: refs/heads/master@{#380192}