[encrypted-media] Idea: Add opaque "label" DOMString member to MediaKeySystemConfiguration

ddorwin has just created a new issue for 
https://github.com/w3c/encrypted-media:

== Idea: Add opaque "label" DOMString member to 
MediaKeySystemConfiguration ==
It is possible that applications will pass long sequences of 
`MediaKeySystemConfiguration`s to `requestMediaKeySystemAccess()`. The
 resulting configuration is accessible via 
`MediaKeySystemAccess.getConfiguration()`, but it may not be easy to 
determine exactly which configuration was selected. This is especially
 true when debugging, but it could also be useful in production 
scenarios. Since the resulting configuration is not the same object 
that was in the sequence passed to `requestMediaKeySystemAccess()`, 
object equality is not possible. Also, custom properties are lost.

Because this use case cannot be solved with custom properties, we 
should consider adding an identifier that user agents will preserve in
 the resulting configuration object. It would have no impact on the 
behavior of the algorithm, including configuration selection. This 
should have very low algorithmic and implementation overhead - lower 
than any other value currently in the dictionary. I propose the 
following for discussion:

```javascript
dictionary MediaKeySystemConfiguration {
  ...
  DOMString label;
};
```

See https://github.com/w3c/encrypted-media/issues/44

Received on Friday, 27 March 2015 22:14:19 UTC