Chrome Version: 56.0.2920.0
Chrome OS Version: 8992.0.0
Chrome OS Platform: All
Network info: Wifi

Please specify Cr-* of the system to which this bug/feature applies (add
the label below).

Steps To Reproduce:
(1) Download below video file and audio file
(2) Right click on shelf, select Autohide shelf 
(3) Start playing audio file in internal audio player
(4) Start playing video in internal Media Player
(5) click on full screen key(F4) on keybord to play in video
(6) Press F4 key for few times

Expected Result:
-- No Ui glitch 

Actual Result:
-- Observing audio player as transparent as shown in below screenshot. 

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always

What is the impact to the user, and is there a workaround? If so, what is
it?

Please provide any additional information below. Attach a screen shot or
log if possible.
Video, audio and screenshot are added below