In r270458 and in RemoteLayerBackingStore::encode(), casting the ImageBuffer and calling the overriding createImageBufferBackendHandle() of the superclass was replaced by casting the backend() and calling its createImageBufferBackendHandle() directly. This may lead to crash if the backend was not created when createImageBufferBackendHandle() is called. The createImageBufferBackendHandle() of the ImageBuffer superclass calls ensureBackendCreated() before calling its createImageBufferBackendHandle(). So we need to replace to call ImageBuffer::backend() to ImageBuffer::ensureBackendCreated().
Created attachment 415606 [details] Patch
Committed r270529: <https://trac.webkit.org/changeset/270529> All reviewed patches have been landed. Closing bug and clearing flags on attachment 415606 [details].
<rdar://problem/72075298>