[presentation-api] Pull Request: Clarified which UA performs the receiving browsing context step

tidoust has just submitted a new pull request for 
https://github.com/w3c/presentation-api:

== Clarified which UA performs the receiving browsing context step ==
The "start a presentation" algorithm was phrased against the 
controlling user agent, but some of the last steps (e.g. "Navigate R 
to presentationUrl") are actually to be performed by the receiving 
user agent. Similarly, the "create a receiving browsing context" 
algorithm mostly applied to the receiving user agent, but the first 
step was to be performed by the controlling user agent.

This commit ensures that the subject remains the same throughout the 
steps of these algorithms. The underlying goal is to ensure that 
algorithms can be linked back to one and only one conformance class, 
to ease testing.

Additional notes:

1. The controlling UA may want to wait for an ack between the step 
where it tells the receiving UA to create the receiving browsing 
context and the step where it establishes the presentation connection 
(steps 21 and 22 in the updated algorithm), but since that is all 
implementation specific, I'm not sure whether it's worth adding 
anything there.
2. I suspect that a receiving user agent is going to use the 
presentation identifier to validate incoming presentation requests 
that it receives. However, the spec currently does not require the 
presentation identifier to be passed to the receiving side when the 
receiving browsing context is created (and thus when the receiving 
user agent starts to monitor incoming presentation connections), only 
when the presentation connection is established. As in 1., this is all
 implementation specific though, so I'm not sure we need to be more 
explicit. Should we also pass the presentation identifier to the 
"create a receiving browser context" algorithm? Should we also be 
explicit that presentation identifiers must match for an incoming 
presentation request to be considered valid?

See https://github.com/w3c/presentation-api/pull/287

Received on Thursday, 28 April 2016 14:13:02 UTC