Record slots in the string table to avoid iterating it twice.

Record slots in the string table to avoid iterating it twice.

Currently we iterate the string table to clear non-live references and
to update pointers. We can skip the second iteration if we record slots.

BUG=

Committed: https://crrev.com/6479d4264a6017401549ab7d2105ae3cc258456d
Cr-Commit-Position: refs/heads/master@{#34936}

[ulan, 2016-03-18 15:20:24]

ulan@chromium.org changed reviewers:
+ hpayer@chromium.org

[ulan, 2016-03-18 15:20:24]

PTAL. This reduces average GC pause in v8.infinite_scroll by ~0.2ms.

[Hannes Payer (out of office), 2016-03-21 09:56:10]

lgtm

[ulan, 2016-03-21 09:58:28]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2016-03-21 09:58:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1814033004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1814033004/1

[commit-bot: I haz the power, 2016-03-21 10:03:56]

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

[commit-bot: I haz the power, 2016-03-21 10:03:57]

Try jobs failed on following builders:
  v8_win_nosnap_shared_compile_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_win_nosnap_shared_compil...)

[ulan, 2016-03-21 11:08:28]

The CQ bit was checked by ulan@chromium.org

[ulan, 2016-03-21 11:08:28]

The patchset sent to the CQ was uploaded after l-g-t-m from hpayer@chromium.org
Link to the patchset: https://codereview.chromium.org/1814033004/#ps20001
(title: " ")

[commit-bot: I haz the power, 2016-03-21 11:08:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1814033004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1814033004/20001

[commit-bot: I haz the power, 2016-03-21 13:26:52]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-03-21 13:28:28]

Description was changed from

==========
Record slots in the string table to avoid iterating it twice.

Currently we iterate the string table to clear non-live references and
to update pointers. We can skip the second iteration if we record slots.

BUG=
==========

to

==========
Record slots in the string table to avoid iterating it twice.

Currently we iterate the string table to clear non-live references and
to update pointers. We can skip the second iteration if we record slots.

BUG=

Committed: https://crrev.com/6479d4264a6017401549ab7d2105ae3cc258456d
Cr-Commit-Position: refs/heads/master@{#34936}
==========

[commit-bot: I haz the power, 2016-03-21 13:28:29]

Patchset 2 (id:??) landed as
https://crrev.com/6479d4264a6017401549ab7d2105ae3cc258456d
Cr-Commit-Position: refs/heads/master@{#34936}