Introduce constants for histogram names in tests.

Introduce constants for histogram names in tests.

BUG=609747
Committed: https://crrev.com/6292cb3b2068b52108e54fcb70c23f1414ca5753
Cr-Commit-Position: refs/heads/master@{#435608}

[pkalinnikov, 2016-12-01 14:08:53]

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

[commit-bot: I haz the power, 2016-12-01 14:09:08]

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

[pkalinnikov, 2016-12-01 14:10:05]

pkalinnikov@chromium.org changed reviewers:
+ engedy@chromium.org

[pkalinnikov, 2016-12-01 14:10:06]

Balazs, PTAL.

[engedy, 2016-12-01 14:11:33]

LGTM.  This makes the tests much easier to read. I would leave the inline
literals in production code, though.

[commit-bot: I haz the power, 2016-12-01 14:58:26]

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

[commit-bot: I haz the power, 2016-12-01 14:58:26]

Dry run: This issue passed the CQ dry run.

[pkalinnikov, 2016-12-01 15:00:31]

The CQ bit was checked by pkalinnikov@chromium.org

[commit-bot: I haz the power, 2016-12-01 15:00:47]

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, 2016-12-01 15:05:04]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480604431318430, "parent_rev":
"2dc4aab725a5cdd9362cdc3eabefbb8601d84ef1", "commit_rev":
"4dc2409be9dd2aaee7f3b52084e0ddc994673494"}

[commit-bot: I haz the power, 2016-12-01 15:05:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-01 15:08:51]

Description was changed from

==========
Introduce constants for histogram names in tests.

BUG=609747
==========

to

==========
Introduce constants for histogram names in tests.

BUG=609747

Committed: https://crrev.com/6292cb3b2068b52108e54fcb70c23f1414ca5753
Cr-Commit-Position: refs/heads/master@{#435608}
==========

[commit-bot: I haz the power, 2016-12-01 15:08:52]

Patchset 1 (id:??) landed as
https://crrev.com/6292cb3b2068b52108e54fcb70c23f1414ca5753
Cr-Commit-Position: refs/heads/master@{#435608}