Docserver: Attach intro metadata to the template itself, not to an object which
contains the template.

BUG=320339
R=yoz@chromium.org, mkearney@chromium.org

Review URL: https://codereview.chromium.org/65643009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235762 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235762