This essentially reverts 1b46a52cfc
and adds more tests.
The reverted change was an incorrect workaround for the real issue,
which was that we weren't creating anonymous wrapper boxes around inline
children of table-cell boxes.
Now that this has been fixed, we can go back to aligning text properly.
This fixes an issue where `vertical-align: middle` would incorrectly
shift the text away from the natural alphabetic baseline.
Fixing this makes many WPT table tests work correctly, so I'm also
importing one of them here. :^)
At computed-value time, this is converted to whatever the parent's
computed value is. So it behaves a little like `inherit`, except that
an inherited start/end value uses the parent's start/end, which might
be different from the child's.
This improves the quality of our font rendering, especially when
animations are involved. Relevant changes:
* Skia fonts have their subpixel flag set, which means that individual
glyphs are rendered at subpixel offsets causing glyph runs as a
whole to look better.
* Fragment offsets are no longer rounded to whole device pixels, and
instead the floating point offset is kept. This allows us to pass
through the floating point baseline position all the way to the Skia
calls, which already expected that to be a float position.
The `scrollable-contains-table.html` ref test needed different table
headings since they would slightly inflate the column size in the test
file, but not the reference.
