Previously, Writer and Edit Engine would skip inserting kashida in words
if the highest-priority candidate position is marked as invalid by
HarfBuzz. This would happen even if the word contained multiple
lower-ranked valid candidate positions.
This change updates Writer and Edit Engine to pass HarfBuzz kashida
position data to the selection algorithm. The algorithm has been updated
to return the highest-priority valid position, if any. The algorithm has
also been updated to use raw positions marked as valid by HarfBuzz as a
fallback, if no better positions could be found.
Change-Id: I40c6432c4607aee197e8767e5667db504469956a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/173963
Tested-by: Jenkins
Reviewed-by: Jonathan Clark <jonathan@libreoffice.org>
d8f430e4be