metrics: Update UpdateEngineErrorCode with new error code.

metrics: Update UpdateEngineErrorCode with new error code.

We just added a new error code to ChromeOS's update_engine so also
update histograms.xml.

BUG=chromium:406546
TEST=Validated the xml, pretty print succeeded.

Committed: https://crrev.com/caf3405875fe6ed8b97ec027a005d0fde264c7d8
Cr-Commit-Position: refs/heads/master@{#292279}

[zeuthen, 2014-08-27 21:41:22]

zeuthen@chromium.org changed reviewers:
+ asvitkine@chromium.org, cmasone@chromium.org, deymo@chromium.org,
isherman@chromium.org, jar@chromium.org, mpearson@chromium.org

[zeuthen, 2014-08-27 21:42:03]

Hi, here's a tiny CL for adding a new error code for ChromeOS's update_engine.
Please review. Thanks!

[Ilya Sherman, 2014-08-27 21:57:11]

LGTM

[zeuthen, 2014-08-27 21:59:21]

The CQ bit was checked by zeuthen@chromium.org

[commit-bot: I haz the power, 2014-08-27 22:00:48]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/zeuthen@chromium.org/514003002/1

[commit-bot: I haz the power, 2014-08-27 23:10:13]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  mac_chromium_compile_dbg on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_comp...)
  mac_chromium_rel_swarming on tryserver.chromium.mac
(http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[commit-bot: I haz the power, 2014-08-28 00:30:33]

Committed patchset #1 (id:1) as eb74ae3df35c2134778b86f5c1ebb9038ef7954f

[commit-bot: I haz the power, 2014-09-10 02:56:01]

Patchset 1 (id:??) landed as
https://crrev.com/caf3405875fe6ed8b97ec027a005d0fde264c7d8
Cr-Commit-Position: refs/heads/master@{#292279}