Intent to implement and ship: CSS prefers-reduced-motion media feature for Windows and MacOSX

[Hiroyuki Ikezoe]

Summary: By using CSS prefers-reduced-motion media feature, web developers
can provide contents depending on a system setting that users want
*motion-less* content. A WebKit blog post [1] might be useful to know
this feature in more detail.

Bugs: https://bugzilla.mozilla.org/show_bug.cgi?id=1365045 for Windows
https://bugzilla.mozilla.org/show_bug.cgi?id=1475462 for Mac OSX

Link to standard:
https://drafts.csswg.org/mediaqueries-5/#prefers-reduced-motion

Platform coverage: Windows and MacOSX
Though I don't have a plan for Android at this moment , I maybe do it
soonish.

Estimated release: For Windows in Firefox 63, for MacOSX it might be
delayed in Firefox 64

Preference behind which this will be implemented: None

Is this feature enabled by default in sandboxed iframes? Yes

If allowed, does it preserve the current invariants in terms of what
sandboxed iframes can do? I believe so

DevTools bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1477920

Do other browser engines implement this?

WebKit already shipped this feature on the last year.

Neither Chrome and Edge hasn't progressed yet.
https://bugs.chromium.org/p/chromium/issues/detail?id=722548
https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/17506002/

web-platform-tests: None
This feature is tied to a system setting, so, as far as I can tell, we
can't write wpt.
WebKit has test cases on their tree controlled by something like our
SpecialPowers. We will have reftests controlled by a UI pref.

Secure contexts: Yes

[1] https://webkit.org/blog/7551/responsive-design-for-motion/

[Boris Zbarsky]

On 7/24/18 3:34 AM, Hiroyuki Ikezoe wrote:
> Secure contexts: Yes

Why?

-Boris

[Boris Zbarsky]

[Tom Ritter]

As far as I can tell the specification does not indicate any privacy
concerns; even though this exposes a system preference.

I'd request that if Resist Fingerprinting is enabled; the browser behaves
as if the user has not set any preference.

-tom

On Tue, Jul 24, 2018 at 2:34 AM, Hiroyuki Ikezoe <hik...@mozilla.com>
wrote:

> _______________________________________________
> dev-platform mailing list
> dev-pl...@lists.mozilla.org
> https://lists.mozilla.org/listinfo/dev-platform
>

[Hiroyuki Ikezoe]

I just realized that I did send below message only to Tom. :)

---------- Forwarded message ----------
From: Hiroyuki Ikezoe <hik...@mozilla.com>
Date: Wed, Jul 25, 2018 at 6:59 AM
Subject: Re: Intent to implement and ship: CSS prefers-reduced-motion media
feature for Windows and MacOSX
To: Tom Ritter <t...@mozilla.com>


Thank you, bz and Tom.

I just filed bug 1478158 for that.