A long time ago, in a galaxy far away, the BlackBerry port used a separate compositing window, effectively juggling two windows for every web page when AC was active. Now, we either use a compositing surface for AC output, which we blend onto the window containing the BackingStore output, or render both BackingStore and AC output directly to one OpenGL capable window surface. The two-window setup is long gone, so simplify the code now that we don't have to consider that case.
Created attachment 135009 [details] Patch
Comment on attachment 135009 [details] Patch I trust you on this one.
Comment on attachment 135009 [details] Patch Clearing flags on attachment: 135009 Committed r112819: <http://trac.webkit.org/changeset/112819>
All reviewed patches have been landed. Closing bug.