There has been several update on the default style sheet of fullscreen elements in the Fullscreen API spec, we should update our ua.css accordingly. Note that we currently have "background: black" in our style sheet while the spec does not have. This line can be removed only when we implement bug 1064843.

https://hg.mozilla.org/integration/mozilla-inbound/rev/8e026b0e24a5a123ab590c9c30968e95fddf1db5 Bug 1215365 - Update ua style sheet of fullscreen element. r=heycam

I had to back this out in https://hg.mozilla.org/integration/mozilla-inbound/rev/4cefc9388515 for gij(19) failures in browser_fullscreen_utility_tray_test.js https://treeherder.mozilla.org/logviewer.html#?job_id=19052256&repo=mozilla-inbound

It doesn't appear to be a permafail, but it did fail 8 out of 9 times so far.

I'm going to reland this patch without removing the z-index line. We would probably need more work to remove that line, especially on gaia side. That line is useless for web content because all fullscreen elements from content other than :root are now rendered in the top layer, while it is not true for <iframe mozbrowser>.

The "background: black" line will be removed in bug 1064843 directly. So this bug no longer depends on that one.

https://hg.mozilla.org/integration/mozilla-inbound/rev/bf2d8f46f02c44512c769689cdcf72aebd50e71e Bug 1215365 - Update ua style sheet of fullscreen element. r=heycam

As m-i has merged my patch for bug 1235470, reland this patch.