It is totally useless to converting the QImage for the QPixmap and then fill the pixmap with zero. Instead of this we can create an empty pixmap with the appropriate dimensions and fill that.
Created attachment 59242 [details] proposed patch
You are right, I did an unfortunate copy-paste there.
Comment on attachment 59242 [details] proposed patch Clearing flags on attachment: 59242 Committed r61540: <http://trac.webkit.org/changeset/61540>
All reviewed patches have been landed. Closing bug.
Revision r61540 cherry-picked into qtwebkit-2.0 with commit 45d1c9149ef8940081fa8dd35854d2b95ebaf3cd