Fix Mac gyp error with disable_nacl

Fix Mac gyp error with disable_nacl

r314575 removed a default `files` array on the `Internet Plug-Ins` Mac
bundle subfolder, so it was only added with disable_nacl=0

This adds an empty default array to match the targets below.

Committed: https://crrev.com/072ef39848b879faa486c76568c1b023524f0fb3
Cr-Commit-Position: refs/heads/master@{#314738}

[tapted, 2015-02-05 02:44:12]

tapted@chromium.org changed reviewers:
+ thakis@chromium.org

[Nico, 2015-02-05 02:50:24]

lgtm

[tapted, 2015-02-05 02:51:01]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2015-02-05 02:52:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/877553010/1

[commit-bot: I haz the power, 2015-02-05 03:43:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-05 03:44:37]

Patchset 1 (id:??) landed as
https://crrev.com/072ef39848b879faa486c76568c1b023524f0fb3
Cr-Commit-Position: refs/heads/master@{#314738}