Test that hiding volume / mute buttons works as expected.

RUN(video.load())
EVENT(canplaythrough)
RUN(window.internals.setAllowHiddenVolumeControls(video, true))
RUN(window.internals.settings.setPreferHiddenVolumeControls(false))
RUN(video.muted = false)
EXPECTED (getComputedStyle(muteButton).display != 'none') OK
EXPECTED (getComputedStyle(volumeSlider).display != 'none') OK
RUN(video.muted = true)
EXPECTED (getComputedStyle(muteButton).display != 'none') OK
EXPECTED (getComputedStyle(volumeSlider).display != 'none') OK
RUN(window.internals.settings.setPreferHiddenVolumeControls(true))
RUN(video.muted = false)
EXPECTED (getComputedStyle(muteButton).display != 'none') OK
EXPECTED (getComputedStyle(volumeSlider).display == 'none') OK
RUN(video.muted = true)
EXPECTED (getComputedStyle(muteButton).display != 'none') OK
EXPECTED (getComputedStyle(volumeSlider).display == 'none') OK
END OF TEST