Hardware jpeg decoding is already disabled in the sandbox for all platforms. For consistency, the ENABLE_HARDWARE_JPEG flag should be removed.
<rdar://problem/78950163>
Created attachment 430754 [details] Patch
It is still present in here: https://searchfox.org/wubkat/rev/c67bb750f2c1083399f0dbe7d08b416cd45eee34/Source/WTF/wtf/PlatformEnableCocoa.h#418 Other call site has been modified or at least, I couldn't find on Searchfox.org.