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.
InlinePaintable was an ad-hoc paintable type required to support the
fragmentation of inline nodes across multiple lines. It existed because
there was no way to associate multiple paintables with a single layout
node. This resulted in a lot of duplicated code between PaintableBox and
InlinePaintable. For example, most of the CSS properties like
background, border, shadows, etc. and hit-testing are almost identical
for both of them. However, the code had to be duplicated to account for
the fact that InlinePaintable creates a box for each line. And we had
quite many places that operate on paintables with a code like:
```
if (box.is_paintable_box()) {
// do something
} else (box.is_inline_paintable()) {
// do exactly the same as for paintable box but using InlinePaintable
}
```
This change replaces the usage of `InlinePaintable` with
`PaintableWithLines` created for each line, which is now possible
because we support having multiple paintables per layout node. By doing
that, we remove lots of duplicated code and bring our implementation
closer to the spec.
Adds additional padding to the end-side of the scrollable overflow
rectangle as necessary to enable a scroll position that satisfies
the requirements of `place-content: end` alignment.
