The WebKitCanvasUsesAcceleratedDrawingPreferenceKey currently has the default value of YES, but should be NO. Clients of WebKit should turn it off, if desired.
Created attachment 90270 [details] Patch
Committed r84306: <http://trac.webkit.org/changeset/84306>
http://trac.webkit.org/changeset/84306 might have broken Windows 7 Release (Tests)