
PASS <iframe>'s about:blank inherits policy. 
PASS <iframe srcdoc>'s inherits policy. 
PASS <iframe src='blob:...'>'s inherits policy. 
PASS <iframe src='data:...'>'s inherits policy. 
PASS <iframe src='javascript:...'>'s inherits policy. 
PASS <iframe sandbox src='blob:...'>'s inherits policy. (opaque origin sandbox)