[Vala] Error attempting to use WebKit-3.0.gir

[bsquared <bwcode4u gmail com>]

How can I use this gir directly.
I get the following errors:

$ valac --pkg gtk+-3.0 --pkg json-glib-1.0 --pkg JSCore-3.0 --pkg
WebKit-3.0   --vapidir . --pkg config gss_js_vala.vala
JSCore-3.0.gir:0.0-0.0: error: The type name `JSGlobalContextRef'
could not be found
JSCore-3.0.gir:0.0-0.0: error: The type name `JSObjectRef' could not be found
gss_js_vala.vala:31.3-31.8: error: The symbol `WebKit' could not be found
                WebKit.WebView webview = new WebKit.WebView();
                ^^^^^^
Compilation failed: 3 error(s), 0 warning(s)


What am I doing wrong?

-- 
Regards,
-Brian