Audio Player disappears on load for .ogg files

Describe the bug: When opening an .ogg audio file the audio player appears for a short time (although broken and with a fullscreen button) but then soon disappears (blank page), the same problem seems to happen with .m4a files. Also when reloading the player disappears almost immediately (maybe 3-4 frames), maybe the player crashes/disappears once we've fetched the file?

To Reproduce:

• Open Servo
• Open a .ogg file (for example: https://ftp.openbsd.org/pub/OpenBSD/songs/song79.ogg )

Platform: Arch Linux (Linux 7.2.4-arch1-2 x86_64), X11/i3, nvidia drivers (615.71.09-1).