This attribute has some compatbility issues...
- The spec says it should be an SVGAnimatedRect which contains
a DOMRect and a DOMReadOnlyRect.
- Blink gives you an SVGAnimatedRect with 2x SVGRect
- Gecko gives you an SVGAnimatedRect with 2x SVGRect? (nullable)
I ended up with something similar to Gecko, an SVGAnimatedRect
with 2x DOMRect? (nullable)
With this fixed, we can now load https://polar.sh/ :^)
This patch makes a few changes to the way we calculate line-height:
- `line-height: normal` is now resolved using metrics from the used
font (specifically, round(A + D + lineGap)).
- `line-height: calc(...)` is now resolved at style compute time.
- `line-height` values are now absolutized at style compute time.
As a consequence of the above, we no longer need to walk the DOM
ancestor chain looking for line-heights during style computation.
Instead, values are inherited, resolved and absolutized locally.
This is not only much faster, but also makes our line-height metrics
match those of other engines like Gecko and Blink.
It does not currently handle any of the actual scripting, but this
should at least allow us to create an instance of the element.
The test being added here isn't actually testing much, but before the
previous commit we used to crash parsing the page due to a TODO().
