On 04/14/2016 02:40 AM, Ms2ger wrote:
>> Preference behind which this will be implemented:
>> layout.css.prefixes.webkit
>
> Should this have a more specific pref?
Absent a compelling reason, no -- it should not.
We're using layout.css.prefixes.webkit here because, without this
-webkit-text-stroke feature, our webkit-prefix support breaks sites.
So, we can't really ship -webkit prefix support without also shipping
support for this feature. And the fewer prefs we have to keep track of
(and to have to worry about enabling/disabling if & when we discover
trouble at the last minute), the better.
Specifically, the dependency is as follows:
(1) The web depends on "-webkit-linear-gradient" as a background.
(2) *But*, it turns out that one common use-case for
-webkit-linear-gradient is to create a background *which is only
intended to be viewed through transparent text*. Some sites (bloomberg
news at least) use "-webkit-text-stroke" as part of this effect.
(3) If we enable layout.css.prefixes.webkit without enabling this one
feature (-webkit-text-stroke), Bloomberg's pull-quotes are unreadable.
Screenshot of what that would look like (taken in Chrome, with the
-webkit-text-stroke declaration manually disabled via devtools):
https://bug1248644.bmoattachments.org/attachment.cgi?id=8719912
(It's a bit more complicated than this; see discussion on
https://bugzilla.mozilla.org/show_bug.cgi?id=1248644 for more details.)
SO: there isn't any graceful fallback if we selectively shipped other
webkit prefixing support without *also* shipping support for this
feature, as shown by the screenshot above. So, it makes sense to combine
it under the umbrella of the same pref.
~Daniel