Add polygon offset doc
Add polygon offset doc

Review URL: http://codereview.chromium.org/155385


git-svn-id: http://src.chromium.org/svn/trunk/src@20456 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: c8552bc7693ab406f0fc5da869b9688a5a3130f1
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser