In bug 1238160, we are exploring allowing mozbrowser frames (or something similar) to be used as an alternative to <xul:browser> on desktop. billm says someone should audit the frameloader/TabParent code to make sure everything works the way we expect on e10s.

:billm, who would be able to do such an audit?

I think it would be fine for you to do it as long as you understand the meaning of all the TabContext stuff. That's mostly what I'm worried about.

I've completed my audit of the code paths surrounding nsFrameLoader and TabContext. I also investigated various Principal, DocShell, and TabContext APIs related to whether things are browser elements, apps, and what their OriginAttributes are, as these are all related to the "non-isolated" <iframe mozbrowser> mode discussed in bug 1238160. The audit has my notes on all these APIs: https://docs.google.com/document/d/1rHVOFhDtko8adpgXxaPvYs6qhAEIdvARVuciVDnKIbk/edit For enabling <iframe mozbrowser> as it is today, I found no issues on the desktop side, so I'll proceed with enabling that plus tests to ensure it's not exposed to content. As for the new non-isolated mode, there are various changes needed across various APIs. I'll describe my plan for this in more detail in bug 1238160.