wstring: text case dirs are always ASCII
wstring: text case dirs are always ASCII

The test_case_dir_, when set, is a relative path like "appcache".

BUG=69467

Review URL: http://codereview.chromium.org/6628065

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@77379 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