Allow null principals to subsume any other principal.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

components/script/dom/bindings/principals.rs

@@ -198,7 +198,6 @@ pub unsafe extern "C" fn subsumes(obj: *mut JSPrincipals, other: *mut JSPrincipa
         let other_origin = other.origin();
         obj_origin.same_origin_domain(&other_origin)
     } else {
-        warn!("Received null JSPrincipals asrgument.");
-        false
+        true
     }
 }