Fix Closure Compiler error which is introduced by crrev.com/1233913010

Fix Closure Compiler error which is introduced by crrev.com/1233913010

BUG=509483
TEST=GYP_GENERATORS=ninja tools/gyp/gyp --depth . ui/file_manager/file_manager/foreground/js/compiled_resources.gyp && ninja -C out/Default

Committed: https://crrev.com/319562c8d45271b5e360abd6a27f0caaa6eb23bc
Cr-Commit-Position: refs/heads/master@{#339847}

[yawano, 2015-07-22 05:14:22]

yawano@chromium.org changed reviewers:
+ mtomasz@chromium.org

[yawano, 2015-07-22 05:14:23]

PTAL. Thank you!

[mtomasz, 2015-07-22 07:51:55]

lgtm!

[yawano, 2015-07-22 07:52:27]

On 2015/07/22 07:51:55, mtomasz wrote:
> lgtm!

Thank you!

[yawano, 2015-07-22 07:52:29]

The CQ bit was checked by yawano@chromium.org

[commit-bot: I haz the power, 2015-07-22 07:52:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1243273003/1

[commit-bot: I haz the power, 2015-07-22 08:36:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-22 08:37:20]

Patchset 1 (id:??) landed as
https://crrev.com/319562c8d45271b5e360abd6a27f0caaa6eb23bc
Cr-Commit-Position: refs/heads/master@{#339847}