Test that 'webkitplaybacktargetavailabilitychanged' event is sent when at least one video element has playable media.

EVENT( webkitplaybacktargetavailabilitychanged )
EXPECTED (event.availability == 'not-available') OK

** simulate device becoming available
EVENT( webkitplaybacktargetavailabilitychanged )

** set src on video that does not have event listener
EVENT( webkitplaybacktargetavailabilitychanged )
EXPECTED (event.availability == 'available') OK

END OF TEST