[mediacapture-screen-share] How to detect Display Surfaces Minimized (#198)

Deuscx has just created a new issue for https://github.com/w3c/mediacapture-screen-share:

== How to detect Display Surfaces Minimized  ==
[Screen Capture](https://www.w3.org/TR/screen-capture/#hidden-display-surfaces) it said that when Display Surfaces enters an inaccessible state will set the muted state to be true. i've tried listen the unmute event `track.onunmute` and `onmute`. but it didn't fired


Please view or discuss this issue at https://github.com/w3c/mediacapture-screen-share/issues/198 using your GitHub account


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