[whatwg] scrdoc and session history don't play along in the spec

[Boris Zbarsky]

The session history algorithm in the spec navigates to urls.  As far as 
I can tell, on the face of it, this means that this testcase:

   <iframe name="x" srcdoc="aaa"></iframe>
   <a target="x" href="http://web.mit.edu">
     Click me, then later hit back
   </a>

should fail to go back.

The good news is that at least WebKit's srcdoc implementation ignores 
the spec here and makes back work, and so will Gecko's.  But the spec 
still needs to be fixed.  Again, as far as I can tell; actually telling 
anything for sure about the navigation/shistory part of the spec is 
impossible.  :(

-Boris