Re: [Page Visibility 2] Request for Comments

On 10/30/14, 11:24 PM, Boris Zbarsky wrote:
> I've already sent my thoughts on this to this list.  I suggest just
> reading those mails if you want to know what I think...

But since, given my past interactions with this working group, I 
somewhat doubt people will do the work of looking it up, let me repeat 
one more time (more or less from 
http://lists.w3.org/Archives/Public/public-web-perf/2014Jan/0040.html 
and following):

1)  This is a backwards-incompatible change (but see item 5 below).
2)  It's a change to behavior that's been shipping for a long time now; 
the last time this came up was nearly a year ago, and _then_ I was 
concerned about content depending on the behavior and suggested that if 
the working group actually wants to make the behavior change it better 
convince implementors to make it ASAP.  That clearly did not happen.
3)  This change is particularly incompatible because it has knock-on 
effects on a number of other specifications and APIs. 
requestAnimationFrame is not the only API affected.
4)  The behavior being suggested for requestAnimationFrame in the "Note" 
in the specification (I know, not normative), doesn't match any UA and I 
fully expect it's not web-compatible, and will assume so until proven 
otherwise.
5)  There are no MUST requirements that result in ever returning 
"hidden", so as far as I can tell all existing UAs are compliant with 
the new spec version.  Which raises the question of what the point of 
the change is, really.

In term's of Mozilla's implementation, what I will probably be 
recommending internally is that we not change our behavior at all, since 
it's already spec-compliant and a known quantity in terms of web compat. 
  If any other UAs do change behavior in some way, and we find out about 
it and think that the change is worth doing for some reason, we'll have 
to reverse-engineer what they're doing exactly, I guess; the spec is not 
particularly helpful here in terms of actually specifying behavior.

-Boris

Received on Friday, 31 October 2014 03:47:23 UTC