Cleanup V8 histograms

Cleanup V8 histograms

- mark obsolete histograms as such
- update descriptions and owners for current histograms
- add missing histograms

BUG=none
R=asvitkine@chromium.org
NOTRY=true

Committed: https://crrev.com/4cbe928ae5e1e83bbff8fa7283604e39274f595e
Cr-Commit-Position: refs/heads/master@{#295054}

[jochen (gone - plz use gerrit), 2014-09-16 11:20:54]

ptal

[Alexei Svitkine (slow), 2014-09-16 13:23:39]

The CQ bit was checked by asvitkine@chromium.org

[Alexei Svitkine (slow), 2014-09-16 13:23:40]

lgtm

[commit-bot: I haz the power, 2014-09-16 13:24:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/563853003/1

[jochen (gone - plz use gerrit), 2014-09-16 13:41:27]

The CQ bit was unchecked by jochen@chromium.org

[jochen (gone - plz use gerrit), 2014-09-16 13:41:41]

The CQ bit was checked by jochen@chromium.org

[commit-bot: I haz the power, 2014-09-16 13:41:57]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/563853003/1

[commit-bot: I haz the power, 2014-09-16 13:42:53]

Committed patchset #1 (id:1) as 7408d4910bd1035294a4ed6cc0614c21e4651a14

[commit-bot: I haz the power, 2014-09-16 13:44:48]

Patchset 1 (id:??) landed as
https://crrev.com/4cbe928ae5e1e83bbff8fa7283604e39274f595e
Cr-Commit-Position: refs/heads/master@{#295054}