[css-shapes] Should shape-margin's computed value be the used value?

Hi All,

I had a quick question about shape-margin's computed value. In the spec, the shape-margin property can be a length or percentage, but computes to an absolute length [1]. In general, I thought that computed values [2] did not resolve percentages when the percentages depended on layout. Is there a reason this property would be different? I know that even with a percentage value as the computed value, the resolved value [3] returned by getComputedStyle might be different, but I would hope they could stay the same. Border-radius [4] is one example of a property that preserves percentages in the computed value.

-Bear Travis

[1] http://dev.w3.org/csswg/css-shapes-1/#shape-margin-property
[2] http://dev.w3.org/csswg/css-cascade/#computed
[3] http://dev.w3.org/csswg/cssom/#resolved-value
[4] http://dev.w3.org/csswg/css-backgrounds/#the-border-radius