Re: [mediacapture-main] Clarification needed on HTMLMediaElement attributes that carry over (#599)

So here's my brief test with https://jsfiddle.net/jib1/avr1w8k0/ basically:
```
    video.onratechange = () => console.log("ratechange");
    video.playbackRate = 0.5;
    console.log(video.playbackRate);
    video.srcObject = await navigator.mediaDevices.getUserMedia({video: true});
    console.log(video.playbackRate);
    video.playbackRate = 0.7;
    console.log(video.playbackRate);
    video.srcObject = null;
    console.log(video.playbackRate);
```
The results show variance and that none are to spec. They all fire ratechange when they shouldn't, and none of them preserve the non-stream value.

Firefox:
```
0.5
ratechange
1
0.7
1
ratechange
```
Chrome: 
```
0.5
ratechange
1
1
1
ratechange
```
Safari:
```
0.5
ratechange
1
0.7
1
ratechange
```
Edge:
```
0.5
ratechange
1
InvalidStateError
```

From my reading of the spec, clarified by https://github.com/w3c/mediacapture-main/pull/600 it should be:
```
0.5
1
1
0.5
```
Is there one we prefer? @youennf @Pehrsons 

-- 
GitHub Notification of comment by jan-ivar
Please view or discuss this issue at https://github.com/w3c/mediacapture-main/issues/599#issuecomment-497499154 using your GitHub account