DevTools: cleanup unused method and constants

DevTools: cleanup unused method and constants

Those became unused after DevTools migrated onto
RecordEnumeratedHistogram method (via patches r324219
in Chromium and r193409 in Blink).

BUG=468026
R=dgozman

Committed: https://crrev.com/1487cb3214949531086cd4ee6ec1f716b7359f45
Cr-Commit-Position: refs/heads/master@{#324606}

[lushnikov, 2015-04-03 14:46:57]

PTAL.

This patch should be landed after the webkit rolled over
https://codereview.chromium.org/1061503002/

[dgozman, 2015-04-03 15:36:49]

lgtm

[lushnikov, 2015-04-09 10:34:38]

lushnikov@chromium.org changed reviewers:
+ tsepez@chromium.org

[lushnikov, 2015-04-09 10:34:39]

tsepez@chromium.org: Please review changes in chrome/browser/devtools/

[Tom Sepez, 2015-04-09 18:06:46]

RS LGTM on deleting code.  Thanks for the cleanup.

[lushnikov, 2015-04-10 08:58:35]

The CQ bit was checked by lushnikov@chromium.org

[lushnikov, 2015-04-10 08:58:36]

The patchset sent to the CQ was uploaded after l-g-t-m from dgozman@chromium.org
Link to the patchset: https://codereview.chromium.org/1060573003/#ps20001
(title: "rebaseline")

[commit-bot: I haz the power, 2015-04-10 08:58:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1060573003/20001

[commit-bot: I haz the power, 2015-04-10 09:51:40]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-04-10 09:52:31]

Patchset 2 (id:??) landed as
https://crrev.com/1487cb3214949531086cd4ee6ec1f716b7359f45
Cr-Commit-Position: refs/heads/master@{#324606}