Once bug 1237726 is fixed, the remaining mixedcontentblocker mochitest that does not run with e10s is test_bug803225.html. The part of the test that does not work is in file_main_bug803225.html under "Test 7: mailto protocol". I think what the test is doing is starting up a link with the mailto: protocol, and checking whether or not it is actually loaded. The way this is being done does not work in a content process.

Blake, would you mind taking a look at this? I saw that you've done some work with e10s protocol handler stuff before. Thanks.

I should have a fix for this tomorrow.

Thanks, Blake!

The web handler app code has to run in the parent process. It opens a new window or tab which then loads in the child (in e10s) and fires the proper observer service obervers.