Sweep map space concurrently.

Sweep map space concurrently.

BUG=chromium:507211
LOG=n

Committed: https://crrev.com/5e52e66591e4d661f0cb740bd56c8c2fbdbbd165
Cr-Commit-Position: refs/heads/master@{#30027}

[Hannes Payer (out of office), 2015-07-06 09:57:59]

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

[Hannes Payer (out of office), 2015-07-06 10:08:03]

Patchset #2 (id:20001) has been deleted

[jochen (gone - plz use gerrit), 2015-07-06 10:10:40]

lgtm

[Hannes Payer (out of office), 2015-08-05 13:10:08]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2015-08-05 13:10:08]

The patchset sent to the CQ was uploaded after l-g-t-m from jochen@chromium.org
Link to the patchset: https://codereview.chromium.org/1226773003/#ps60001
(title: " ")

[commit-bot: I haz the power, 2015-08-05 13:10:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1226773003/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1226773003/60001

[commit-bot: I haz the power, 2015-08-05 13:11:44]

Committed patchset #3 (id:60001)

[commit-bot: I haz the power, 2015-08-05 13:12:08]

Patchset 3 (id:??) landed as
https://crrev.com/5e52e66591e4d661f0cb740bd56c8c2fbdbbd165
Cr-Commit-Position: refs/heads/master@{#30027}

[Hannes Payer (out of office), 2015-08-18 05:37:54]

Patchset #4 (id:80001) has been deleted

[Hannes Payer (out of office), 2015-08-18 07:57:59]

Patchset #4 (id:100001) has been deleted

[Hannes Payer (out of office), 2015-08-26 08:31:51]

Patchset #4 (id:120001) has been deleted