Intent to Remove: CSS -webkit-transition media feature (PrefixedTransitionMediaFeature)

[Philip Jägenstedt]

Primary eng (and PM) emails

phi...@opera.com

Summary

Remove the CSS -webkit-transition media feature.

Note that this isn't the same as the -webkit-transition property, that's very far from dead:

http://www.chromestatus.com/metrics/css/timeline/popularity/332

Motivation

It has been deprecated as PrefixedTransitionMediaFeature since May 2013 (r150503).

Usage information from UseCounter

This was on pdr's list <http://crbug.com/332191> of features which are "unused or have extremely low usage numbers". The use counter is old enough to have been in the stable channel for a while now.

Compatibility Risk

@media (-webkit-transition) will stop matching and its style rules not applied, which is of course already the case in non-WebKit browsers.

Row on feature dashboard?

No.

[Eric Seidel]

lgtm

[TAMURA, Kent]

lgtm 2

--
TAMURA Kent
Software Engineer, Google

[PhistucK]

There are a lot of totally non standard -webkit-(CSS-feature-name), if I remember correctly. Are all of them tracked as well?

☆PhistucK

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[Jochen Eisinger]

lgtm3

[Adam Barth]

On Fri, Jan 17, 2014 at 5:04 AM, PhistucK <phis...@gmail.com> wrote:

There are a lot of totally non standard -webkit-(CSS-feature-name), if I remember correctly. Are all of them tracked as well?

Yes, they're all listed here:

http://www.chromestatus.com/metrics/css/popularity

 

Adam

[PhistucK]

I was referring to the CSS media query features, not CSS properties.
-webkit-transform-2d
-webkit-transform-3d
And more.

☆PhistucK

[Philip Jägenstedt]

No other media query features, prefixed or otherwise, had use
counters, so I'll add them:

https://codereview.chromium.org/141163011

If the bots are happy with that, I'll create a bug and submit it for review.

Philip

[PhistucK]

Thank you very much!

Regarding -webkit-view-mode - I think it should be outright removed. It apparently does not work anyway (unless things changed since 2010 in this regard?).

☆PhistucK

[Philip Jägenstedt]

Even if it doesn't work it's still distinguishable from the feature
not existing, so I'd just wait for the use counter data before
removing it. You're free to try an Intent to Deprecate and Remove, of
course, if there are strong reasons despite lacking use counter data.

Philip

[PhistucK]

How is a media query feature distinguishable? perhaps from the CSSOM side? oh, well. No need to rush it, then.

☆PhistucK

[Philip Jägenstedt]

Here's an example:

http://software.hixie.ch/utilities/js/live-dom-viewer/saved/2767

In browsers that don't support -webkit-view-mode the page is green. In
Blink/WewKit it is red.

Philip

[PhistucK]

Right! Sorry, thank you for the clarification.

☆PhistucK

[m.g...@gmail.com]

On Friday, January 17, 2014 8:20:33 AM UTC+1, Philip Jägenstedt wrote:

Note that this isn't the same as the -webkit-transition property, that's very far from dead:

http://www.chromestatus.com/metrics/css/timeline/popularity/332

Does that include sites that define both -webkit-transition & transition? Because that metric would be kind of useless considering the prefix is needed for a lot of older mobile browsers.

It would be interesting to know how many sites use -webkit-transition without the standard version.

[Philip Jägenstedt]

I don't know exactly what counters chromestatus metrics are hooked to,
so I can't answer that, but I would guess that it's simply counting
the properties without doing anything fancy.

Philip

[Max Heinritz]

Chromestatus.com just reports raw property occurrences, so pages with both the prefixed and unprefixed versions are indeed counted in the -webkit-transition totals.  But we can calculate a lower bound on the number of pages using just the prefixed version:

% of measured web pages loaded in Chrome with the relevant properties:

transition: ~39%

-webkit-transition: ~50%

This suggests that at least 50% - 39% = 11% of measured pages just use -webkit-transition.

Does that math seem right?

Philip

[Tab Atkins Jr.]

Yeah, that's probably right (and is in rough accord with what I
suspected the numbers were).

~TJ