Fix a couple small problems with tools/unused-grit-header.py.

Fix a couple small problems with tools/unused-grit-header.py.

- Checking the wrong nodes due to a typo in the previous code review.
- Handle the case of GRD files that do not emit a header file.

NOTRY=true

Committed: https://crrev.com/e1608a4fc7ece209109ca3a69c32b23a880ed41f
Cr-Commit-Position: refs/heads/master@{#292062}

[Lei Zhang, 2014-08-27 00:52:18]

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

[Lei Zhang, 2014-08-27 00:52:18]

Bleh

[Nico, 2014-08-27 00:53:15]

lgtm with s/omit/emit/ in the description (i think)

[Lei Zhang, 2014-08-27 01:00:46]

On 2014/08/27 00:53:15, Nico (hiding) wrote:
> lgtm with s/omit/emit/ in the description (i think)

Indeed. Done.

[Lei Zhang, 2014-08-27 01:00:48]

The CQ bit was checked by thestig@chromium.org

[commit-bot: I haz the power, 2014-08-27 01:01:34]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/thestig@chromium.org/510623002/1

[commit-bot: I haz the power, 2014-08-27 01:12:14]

Committed patchset #1 (1) as 9761e6921ca31e85321448edc066de4c87cefbea

[tfarina, 2014-08-27 19:21:23]

tfarina@chromium.org changed reviewers:
+ tfarina@chromium.org

[tfarina, 2014-08-27 19:21:23]

lgtm (rubber-stamp).

[commit-bot: I haz the power, 2014-09-10 02:48:31]

Patchset 1 (id:??) landed as
https://crrev.com/e1608a4fc7ece209109ca3a69c32b23a880ed41f
Cr-Commit-Position: refs/heads/master@{#292062}