Docserver: Fix property type rendering issue after r235216.

TBR=yoz@chromium.org

Review URL: https://codereview.chromium.org/67473006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235272 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235272