Add test for seamless iframes
Add test for seamless iframes

mpopp75/html5test,mpopp75/html5test,chiefcll/html5test,ya7lelkom/html5test,chiefcll/html5test,NielsLeenheer/html5test,ya7lelkom/html5test,NielsLeenheer/html5test,chiefcll/html5test,mpopp75/html5test,ya7lelkom/html5test,NielsLeenheer/html5test