Fix path to omnibox_focus_state.h in omnibox.gypi

Fix path to omnibox_focus_state.h

In change https://codereview.chromium.org/1224203003 the path to
omnibox_focus_state.h was set to a non-existent location. This isn't
a serious problem because it's just a header file. This mistake isn't
detected when generating ninja files from .gyp files unless msvs-ninja
is selected as one of the GYP_GENERATORS.

With msvs-ninja the error is revealed with this message:
Warning: Missing input files:
D:\src\chromium\src\components\omnibox\omnibox_focus_state.h

R=pkasting@chromium.org
BUG=483424
Committed: https://crrev.com/b902fbc9a8db79ab04476320dadceeb0bf83b571
Cr-Commit-Position: refs/heads/master@{#338733}

[Peter Kasting, 2015-07-14 19:51:54]

The CQ bit was checked by pkasting@chromium.org

[Peter Kasting, 2015-07-14 19:51:54]

lgtm

[commit-bot: I haz the power, 2015-07-14 19:52:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1240713002/1

[commit-bot: I haz the power, 2015-07-14 20:53:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-14 20:53:55]

Patchset 1 (id:??) landed as
https://crrev.com/b902fbc9a8db79ab04476320dadceeb0bf83b571
Cr-Commit-Position: refs/heads/master@{#338733}

[blundell, 2015-07-15 09:04:28]

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

[blundell, 2015-07-15 09:04:29]

Thanks!