Fix typo in base/values.cc from r249102, add a test

BUG=341797

Review URL: https://codereview.chromium.org/137813005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250537 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250537