Docserver: Run the ContentProviders Cron() method on a standard request if a
patch changes content_providers.json.

R=yoz@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/66583006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234275 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234275