Fix closure compiler error which is caused by crrev.com/1165913003.

Fix closure compiler error which is caused by crrev.com/1165913003.

BUG=488227
TEST=GYP_GENERATORS=ninja tools/gyp/gyp --depth . ui/file_manager/gallery/js/compiled_resources.gyp && ninja -C out/Default

Committed: https://crrev.com/76ab89d6c645325efada623e00f232c518a05460
Cr-Commit-Position: refs/heads/master@{#332821}

[yawano, 2015-06-04 11:49:21]

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

[yawano, 2015-06-04 11:49:21]

PTAL. Thank you!

[fukino, 2015-06-04 12:22:54]

The CQ bit was checked by fukino@chromium.org

[fukino, 2015-06-04 12:22:55]

lgtm

[commit-bot: I haz the power, 2015-06-04 12:23:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1151503006/1

[commit-bot: I haz the power, 2015-06-04 12:25:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-04 12:26:44]

Patchset 1 (id:??) landed as
https://crrev.com/76ab89d6c645325efada623e00f232c518a05460
Cr-Commit-Position: refs/heads/master@{#332821}