Fix an exception in BatterMonitorFactory

Fix an exception in BatterMonitorFactory

Use a copy of the set to avoid ConcurrentModificationException.

BUG=669294
Committed: https://crrev.com/e4c28faf93413833defafbc736a380d4c41b4a1b
Cr-Commit-Position: refs/heads/master@{#435467}

[Jinsuk Kim, 2016-11-30 07:29:17]

jinsukkim@chromium.org changed reviewers:
+ timvolodine@chromium.org

[timvolodine, 2016-11-30 13:31:02]

lgtm,
any ideas why this happens? is this because of reentrancy and unsubscribe() can
be called via monitor.didChange()?

[Jinsuk Kim, 2016-11-30 22:43:13]

On 2016/11/30 13:31:02, timvolodine wrote:
> lgtm,
> any ideas why this happens? is this because of reentrancy and unsubscribe()
can
> be called via monitor.didChange()?

Looks like it, but didn't delve deep enough to find the exact flow.

[Jinsuk Kim, 2016-11-30 22:43:27]

The CQ bit was checked by jinsukkim@chromium.org

[commit-bot: I haz the power, 2016-11-30 22:43:57]

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, 2016-11-30 23:18:59]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480545807069200, "parent_rev":
"7986318cfe1397ac4c84934705b5f90cc335397b", "commit_rev":
"5e1843f036fa0c674a8e640f00446d1ea63c28ca"}

[commit-bot: I haz the power, 2016-11-30 23:19:25]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-30 23:22:45]

Description was changed from

==========
Fix an exception in BatterMonitorFactory

Use a copy of the set to avoid ConcurrentModificationException.

BUG=669294
==========

to

==========
Fix an exception in BatterMonitorFactory

Use a copy of the set to avoid ConcurrentModificationException.

BUG=669294

Committed: https://crrev.com/e4c28faf93413833defafbc736a380d4c41b4a1b
Cr-Commit-Position: refs/heads/master@{#435467}
==========

[commit-bot: I haz the power, 2016-11-30 23:22:46]

Patchset 1 (id:??) landed as
https://crrev.com/e4c28faf93413833defafbc736a380d4c41b4a1b
Cr-Commit-Position: refs/heads/master@{#435467}