With the following viewport meta-tag, you can still double-tap zoom the page:
<meta name="viewport" content="user-scalable=no, target-density-dpi=device-dpi,
Created attachment 137654 [details]
Comment on attachment 137654 [details]
Clearing flags on attachment: 137654
Committed r114488: <http://trac.webkit.org/changeset/114488>
All reviewed patches have been landed. Closing bug.