DrawingArea::updateBackingStoreState() is not used on Apple platforms. <rdar://problem/61802011>
Created attachment 396603 [details] Patch v1
Comment on attachment 396603 [details] Patch v1 r=me
Committed r260177: <https://trac.webkit.org/changeset/260177> All reviewed patches have been landed. Closing bug and clearing flags on attachment 396603 [details].