Don't force callers to be ASCII (when some of them already aren't).

TBR=tfarina
BUG=none
TEST=none
Review URL: http://codereview.chromium.org/3137015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56451 0039d316-1c4b-4281-b951-d872f2087c98