Patch forthcoming.
All of our other protocols start with capital letters. Primitive should be "Primitive", not "primitive".
Created attachment 321198 [details] the patch
Comment on attachment 321198 [details] the patch r=me
Landed in https://trac.webkit.org/changeset/222215/webkit
<rdar://problem/34693239>
Migrated to https://github.com/gpuweb/WHLSL/issues/189