Files.app: Fix typo in onUnload_ handler.

Files.app: Fix typo in onUnload_ handler.

The type causes an exception and it prevent the app from running
progressCenter.removePanel.

So the disposed ProgressCenterPanel remains in the ProgressCenter and it causes
another bug.

BUG=418517
TEST=repo steps of the bug.

Committed: https://crrev.com/26acebd1856c8de0a2a89da2e73fe7ccec160f30
Cr-Commit-Position: refs/heads/master@{#297353}

[hirono, 2014-09-30 01:52:23]

hirono@chromium.org changed reviewers:
+ iseki@chromium.org

[hirono, 2014-09-30 01:52:24]

PTAL the CL? Thank you!

[iseki, 2014-09-30 02:06:49]

LGTM.
Thank you for fixing my typo.

[hirono, 2014-09-30 02:14:06]

The CQ bit was checked by hirono@chromium.org

[hirono, 2014-09-30 02:14:11]

On 2014/09/30 02:06:49, iseki wrote:
> LGTM.
> Thank you for fixing my typo.

Thanks!

[commit-bot: I haz the power, 2014-09-30 02:15:48]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/618563002/1

[commit-bot: I haz the power, 2014-09-30 02:15:49]

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

[commit-bot: I haz the power, 2014-09-30 02:15:50]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[hirono, 2014-09-30 02:27:49]

hirono@chromium.org changed reviewers:
+ yoshiki@chromium.org

[hirono, 2014-09-30 02:27:50]

@yoshiki - PTAL the CL? Thank you!

[hirono, 2014-09-30 03:08:01]

hirono@chromium.org changed reviewers:
+ fukino@chromium.org
- yoshiki@chromium.org

[hirono, 2014-09-30 03:08:02]

@yoshiki is on vacation.
@fukino PTAL? Thank you!

[fukino, 2014-09-30 03:17:59]

On 2014/09/30 03:08:02, hirono wrote:
> @yoshiki is on vacation.
> @fukino PTAL? Thank you!

lgtm

[hirono, 2014-09-30 03:18:41]

The CQ bit was checked by hirono@chromium.org

[hirono, 2014-09-30 03:18:53]

Thank you!

[commit-bot: I haz the power, 2014-09-30 03:27:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/618563002/1

[commit-bot: I haz the power, 2014-09-30 03:32:34]

Committed patchset #1 (id:1) as afe4248d8bce8e7b1506f9c0dbf63b186579dae7

[commit-bot: I haz the power, 2014-09-30 03:33:27]

Patchset 1 (id:??) landed as
https://crrev.com/26acebd1856c8de0a2a89da2e73fe7ccec160f30
Cr-Commit-Position: refs/heads/master@{#297353}