This test has an <iframe> with a deferred script that calls a function in the parent document. According to bz the semantics here are that the iframe script can start executing as soon as the <iframe> is done being parsed, which may be before the parent script has finished parsing and the function installed on the global. This is breaking in supersnappy, which is evaluating the scripts in this ordering.
Created attachment 630393 [details] [diff] [review] patch This causes the parent.done() call to work and the test to pass with supersnappy.
Created attachment 630397 [details] [diff] [review] patch Now with the correct patch.
Comment on attachment 630397 [details] [diff] [review] patch r=me
https://hg.mozilla.org/mozilla-central/rev/e758973c6ab1 (Merged by Ed Morley)