Fix a ConcurrentModificationException issue

Fix a ConcurrentModificationException issue

Shouldn't remove items from a hashmap while iterating it.
Instead, use an iterator and call iterator.remove().

BUG=630218
Committed: https://crrev.com/4106f1c294c9a4e90e273d1600b302f28f9dd9a4
Cr-Commit-Position: refs/heads/master@{#406958}

[qinmin, 2016-07-21 20:02:15]

qinmin@chromium.org changed reviewers:
+ michaelbai@chromium.org

[qinmin, 2016-07-21 20:02:16]

PTAL

[michaelbai, 2016-07-21 20:06:30]

lgtm

[qinmin, 2016-07-21 20:38:46]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2016-07-21 20:39:11]

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, 2016-07-21 21:49:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-21 21:50:17]

Description was changed from

==========
Fix a ConcurrentModificationException issue

Shouldn't remove items from a hashmap while iterating it.
Instead, use an iterator and call iterator.remove().

BUG=630218
==========

to

==========
Fix a ConcurrentModificationException issue

Shouldn't remove items from a hashmap while iterating it.
Instead, use an iterator and call iterator.remove().

BUG=630218

Committed: https://crrev.com/4106f1c294c9a4e90e273d1600b302f28f9dd9a4
Cr-Commit-Position: refs/heads/master@{#406958}
==========

[commit-bot: I haz the power, 2016-07-21 21:50:18]

Patchset 1 (id:??) landed as
https://crrev.com/4106f1c294c9a4e90e273d1600b302f28f9dd9a4
Cr-Commit-Position: refs/heads/master@{#406958}