(Filing a separate bug as requested by Sylvestre.) The part 3 patch for bug 1342951 has caused OOB bug 1402109. I should have a fix for that soon, but I don't feel comfortable uplifting that fix at this stage. I'd rather back out the patches that caused the issue from 57 and only fix the bug on 58 (Nightly).

Approval Request Comment [Feature/Bug causing the regression]: bug 1342951 [User impact if declined]: OOB [Is this code covered by automated tests?]: yes [Has the fix been verified in Nightly?]: by virtue of being how the code worked prior to bug 1342951 landing, yes [Needs manual test from QE? If yes, steps to reproduce]: no [List of other uplifts needed for the feature/fix]: none [Is the change risky?]: no [Why is the change risky/not risky?]: backing out to known good state [String changes made/needed]: none

Comment on attachment 8912703 [details] [diff] [review] Backout bug 1342951 part 3 (302d9e49ac75) for causing bug 1402109 Fix some crashes, taking it. Should be in 57b4

https://hg.mozilla.org/releases/mozilla-beta/rev/c98ecac85244 https://hg.mozilla.org/releases/mozilla-beta/rev/961888633c2c

All 3 crash bugs depending on this are confirmed no longer crashing on Beta.