The BackingStore memory is shared by all web pages. We should check if the current backingStore is active before create/release this shared memory.
Created attachment 162223 [details] patch
Comment on attachment 162223 [details] patch commit
Comment on attachment 162223 [details] patch Clearing flags on attachment: 162223 Committed r127600: <http://trac.webkit.org/changeset/127600>
All reviewed patches have been landed. Closing bug.