[Fontations] Switch usage of Fontations for web fonts to experimental
After https://crrev.com/c/5913023/ created a virtual test suite to
continue running FreeType tests on virtual/text-antialias, upgrade
FontationsFontBackend to experimental. This means on Android, Linux and
ChromeOS, all web font usage will go through Fontations. On Windows and
Mac, all unsupported-by-system-renderer web font usage will go through
Fontations.
Preparation for an experiment rollout and fieldtrial_testing_config.json
which activates the flag.
Bug: chromium:40045339, chromium:371534780
Change-Id: Ic3d1be4a7621d545eba6f35d04e45074e8b505e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5913383
Commit-Queue: Dominik Röttsches drott@chromium.org
Reviewed-by: Ian Kilpatrick ikilpatrick@chromium.org
Cr-Commit-Position: refs/heads/main@{#1365687}