Check the input parameter returned by libcros.
Check the input parameter returned by libcros.

Libcros can return an empty string and fallback to en_US in such a case for ease of development.

BUG=chromium-os:6268
TEST=manual

Review URL: http://codereview.chromium.org/6410055

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@73602 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser