Blink does not prevent <video controls tabindex="-1">
getting focus when using the Tab key.
I assume this is because the player controls are provided in a ShadowRoot that does not realize its ShadowHost was removed from the
document's tab sequence (by way of `tabindex="-1"`). Focusing the video element by Tab can be avoided by removing the
controls
attribute, but I assume that has other undesired side effects.
Note that you need to hit Tab several times because the video controls are also in the tab sequence, but you won't *see* them actually having focus.
Also note that the second video element (the one not supposed to get focus), emits a focus
event, but does not render the focus outline