If the site doesn't ask for a reasonable font and the system doesn't provide a good fallback, FontFallBackList::primaryFontData can be 0.
Created attachment 145335 [details]
Comment on attachment 145335 [details]
There are many places in the code that require primaryFontData to be non-0. This bug should be fixed in the FontCache implementation so that it always provides some font as a last resort.
Created attachment 145375 [details]
Comment on attachment 145375 [details]
Clearing flags on attachment: 145375
Committed r119340: <http://trac.webkit.org/changeset/119340>
All reviewed patches have been landed. Closing bug.