An additional syscall needs to be added to the sandbox allow list.
rdar://problem/48829655
Created attachment 364818 [details] Patch
Comment on attachment 364818 [details] Patch r=me
Created attachment 364819 [details] Patch
The patch was already reviewed when I uploaded an additional patch. I will just land the new patch, which has no significant changes from the one which was approved. Thanks for reviewing!
Committed r243329: <https://trac.webkit.org/changeset/243329/webkit>.