The DrawingBuffer constructors and destructors for Cairo, Qt, and Mac are almost identical. I assume non-Cairo Windows should do the same thing. I'm not sure because Clutter and BlackBerry have significant differences from the other ports' constructors and destructors.
The Mac constructor has Objective C calls inside it, so it can't easily be refactored to a C++ file, but the Cairo and Qt constructors can be combined.
Created attachment 205834 [details]
Comment on attachment 205834 [details]
Clearing flags on attachment: 205834
Committed r152269: <http://trac.webkit.org/changeset/152269>
All reviewed patches have been landed. Closing bug.