The current code path for handling web fonts uses 'AddFontMemResourceEx'. Unfortunately, this only updates the font caches used by GDI, and is not exposed to DirectWrite.
This patch does the following:
1. Moves some code into a new DirectWriteUtilities file, similar to how Direct2D is handled, so we can share code in more places.
2. After adding the font to GDI, it adds the font information to the DirectWrite font cache.
3. Add logic to check the overall system DirectWrite fonts, as well as the custom font cache used for downloaded fonts.
Created attachment 376393 [details]
Created attachment 376410 [details]
Created attachment 376411 [details]
Comment on attachment 376411 [details]
Clearing flags on attachment: 376411
Committed r248748: <https://trac.webkit.org/changeset/248748>
All reviewed patches have been landed. Closing bug.