Added validity check to BeatsMusicController so that album art actually exists on page
Added validity check to BeatsMusicController so that album art actually exists on page

ahmedalsudani/chrome-media-keys,cwal/chrome-media-keys,PeterMinin/chrome-media-keys,msfeldstein/chrome-media-keys,PeterMinin/chrome-media-keys,cwal/chrome-media-keys,ahmedalsudani/chrome-media-keys