Intent to unship: nonzero unitless MathML lengths

[Frédéric Wang]

Hi,

In bug 1574749, I intend to unship nonzero unitless MathML lengths.
MathML 3 says that things like mathsize="2" should be interpreted as
mathsize="200%" but discourages that use [1]:

> A trailing "%" represents a percent of a reference value; unless
otherwise stated, the reference value is the default value. [...] A
number without a unit is intepreted as a multiple of the reference
value. This form is primarily for backward compatibility and should be
avoided, preferring explicit units for clarity.

Unitless values have been implemented in WebKit and Gecko. We have sent
deprecation warning since Mozilla 20 (released 6 years ago) [2].

MathML2 was less consistent regarding how to handle unitless attribute
values but at least "0" is always accepted [3]. The MathML CG agreed
to align with CSS and only accept the unitless value "0" in MathML
Core [4].

[1] https://www.w3.org/TR/MathML3/chapter2.html#fund.units
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=553917
[3] https://www.w3.org/TR/MathML2/chapter2.html#fund.units
[4] https://github.com/mathml-refresh/mathml/issues/24

--
Frédéric Wang