Playing videos on Twitter is not working and freezing the mobile browser

We got a report on our blog that Tor Browser for Android is not playing videos on Twitter and is stopping (I assume it is meant freezing/crashing). See: https://blog.torproject.org/comment/280334#comment-280334.

I reproduced that by playing the video on https://twitter.com/thezdi/status/1108828979425738753, both with 8.5a8 and 8.5a9.

Marking at least the investigation as blocking TB 8.5.

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