Move RemoteLayerBackingStore::Buffer.isVolatile into ImageBufferBackend
Created attachment 454177 [details] Patch
Created attachment 454178 [details] Patch
<rdar://problem/89999926>
Committed r291053 (248227@main): <https://commits.webkit.org/248227@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 454178 [details].