Make http result code histograms show the value too.

Make http result code histograms show the value too.

Often, when looking at histograms using these, it's
much easier to go by the code than the name, so
show both.

BUG=none
NOTRY=true

Committed: https://crrev.com/f172268a30fc43a836a80fc68d7ce242ddcd05d0
Cr-Commit-Position: refs/heads/master@{#297259}

[Alexei Svitkine (slow), 2014-09-29 20:18:29]

asvitkine@chromium.org changed reviewers:
+ isherman@chromium.org

[Ilya Sherman, 2014-09-29 21:02:16]

LGTM, thanks.

[Ilya Sherman, 2014-09-29 21:02:29]

The CQ bit was checked by isherman@chromium.org

[commit-bot: I haz the power, 2014-09-29 21:04:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/617533002/1

[commit-bot: I haz the power, 2014-09-29 21:07:21]

Committed patchset #1 (id:1) as 6e3839010f9ffb3d8402156e1e481b7e10bdedb1

[commit-bot: I haz the power, 2014-09-29 21:09:28]

Patchset 1 (id:??) landed as
https://crrev.com/f172268a30fc43a836a80fc68d7ce242ddcd05d0
Cr-Commit-Position: refs/heads/master@{#297259}