Added visibility observer

[yoavweiss]

During the Velocity summit there were multiple requests by large Web sites to be able to better track performance by being able to tell when certain elements have been laid out by the browser.

[natduca]

does it really make sense for us to list our future predicted work in the charter? i'm a bit of an outsider to the process parts of things but i tend to find language about scope to be more effective when you take your future expected work and convert it into areas of interest.

in this context, i recall the perf wg charter saying pretty clearly that we do perf apis only when we absolutely must do them, and that our first and primary charter was for performance monitoring.

thats grey area but here i feel the same thing. is VO here or houdini for instance? If we claim every api that helps with performance, then we're taking on too much.

@igrigorik thoughts?

[igrigorik]

I agree, committing to an API, like Visibility Observer feels a bit premature. That said, we do have a lot of developer feedback that gets routed to folks that work in the webperf group, and ~"visibility observer" is a recurring theme. As such, it is something we should investigate: draft a problem statement, list the use cases, document existing approaches/hacks... It's not at all clear (to me, at least) as to how, and where this problem needs to be solved. It could well be the case that the results of above exploration indicate that this should be solved elsewhere (or not at all).

I'm not sure how to capture this best in W3C-friendly-legaleze though. /cc @plh @toddreifsteck @tobint

[natduca]

@slightlyoff is visibility observer even appropriate for webperf? It seems like houdini here.

[slightlyoff]

It's hard to tell. I asked about this at the TAG meeting with Ilya and we
didn't have a strong take-away. Houdini or DOM seem appropriate in the
short-run.

On Tue, Apr 21, 2015 at 10:28 AM, Nat Duca notifications@github.com wrote:

@slightlyoff https://github.com/slightlyoff is visibility observer even
appropriate for webperf? It seems like houdini here.

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Reply to this email directly or view it on GitHub
#1 (comment).

[igrigorik]

Based on the discussion on our webperf conf call earlier this week, plus the discussion at the TAG meeting... I think Visibility Observer falls into our "use cases" [1] bucket. Which is to say, the group gets a lot of feedback about the problem, and while webperf-wg may not be the right place to spec/solve it we should, at a minimum, document the feedback and route it to appropriate places (TAG, or elsewhere).

Closing this, feel free to reopen if needed.

[1] a7d4095