Browsers such as Chrome and Firefox apply an arbitrary scale to the
current font size if `normal` is used for `line-height`. Firefox uses
1.2 while Chrome uses 1.15. Let's go with the latter for now, it's
relatively easy to change if we ever want to go back on that decision.
This also requires updating the expectations for a lot of layout tests.
The upside of this is that it's a bit easier to compare our layout
results to other browsers', especially Chrome.
This change should move us forward toward emoji support, as we are no
longer limited by our own OpenType implementation, which was failing
to parse the TrueType Collection format used to store emoji fonts
(at least on macOS).
When traversing the layout tree to find an appropriate box child to
derive the baseline from. Only the child's margin and offset was being
applied. Now we sum each offset on the recursive call.
Previously, setting CSS `line-height: 0` on an `input` element would
result in no text being displayed.
Other browsers handle this by setting the minimum height to the
"normal" value for single line inputs.
