Render tofu using first candidate font rather than last resort

When all fonts have been exhausted and we must render tofu / notdef, we
use the first candidate font rather than the system or last resort font.

This helps in the case where a user has specified a monospace font such
as for the terminal system app. We want to use the uniform width tofu,
rather than the system or last resort font.

Renamed is_last_resort to is_last_font in HarfBuzzShaper to reduce
confusion since the final font used may not be the system last
resort font.

Some tests required updating since they are now rendering .notdef from
the preferred font rather than the last resort font. I have added
SansNotoTibetan-Regular.ttf font which is required in test

Cq-Include-Trybots: luci.chromium.try:linux-blink-rel;luci.chromium.try:mac10.10-blink-rel;luci.chromium.try:mac10.11-blink-rel;luci.chromium.try:mac10.12-blink-rel;luci.chromium.try:mac10.13-blink-rel;luci.chromium.try:mac10.13_retina-blink-rel;luci.chromium.try:mac10.14-blink-rel;luci.chromium.try:mac10.15-blink-rel;luci.chromium.try:win7-blink-rel;luci.chromium.try:win10-blink-rel
Bug: 1090566
Change-Id: Ifca2800e6296adac3e40e3dae16008959b669337
Reviewed-by: Robert Ma <>
Reviewed-by: Emil A Eklund <>
Reviewed-by: Dominik Röttsches <>
Commit-Queue: Joel Hockey <>
Cr-Commit-Position: refs/heads/master@{#776171}
GitOrigin-RevId: 1c0065a8f801f048e06ee7a4572704a8e5fae6a8
3 files changed