(Big) Testcase: http://nt1m.github.io/silhouette-audio-player/
Created attachment 8659447 [details] testcase.html reduced testcase. I haven't tried to remove the file input, but this is already a reduced testcase.
Pushlog: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=4f33bf3be1d07b080197cd8231c6365673c25fd7&tochange=0021aceac846 Regressed by: Bug 901633
Via local build, Last Good: 5b18471f2ff7 First Bad: f13da3f6b494
Recent regression in 43, tracking. Paul is this something you might take a look at?
I'm landing the patch today, it's in bug 1203836.
The patch in bug 1203836 was uplifted to aurora 43, so I'm marking this fixed as well.