This commit removes the possibility to construct BidiParagraph and
BidiLine objects with non-zero offsets. We don't use these features,
and the assumption that these offsets are always zero simplifies our
visual ordering algorithm.
Prior to this commit we overallocated the s32 buffer. The buffer was
unnecessarily padded by zeros, and the line stating this, wasn't
actually dropping the null terminator.
This change also fixes bad access that could happen with \r\n
line terminators. An incorrectly sized buffer meant that \n was
clobbered by the null terminator.
Previously using the FontForRange type was motivated by hiding the
RangedValues type in case we wanted to expose the ShapedText API. This
introduced unnecessary conversions between FontForRange and
RangedValues<Font>.
