POSIX: Have pref service save paths as UTF8.
POSIX: Have pref service save paths as UTF8.

We were passing the raw path string to StringValue, but
StringValue expects strings to be UTF8.  There's only
a DCHECK to enforce this, so I imagine it was working
silently before.

This will break for users that don't currently have UTF8
file names, but it will now work going forward.

Review URL: http://codereview.chromium.org/201027


git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@25555 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