Add WebDX feature mapping for prefers-contrast and prefers-reduced-transparency.
Change-Id: I2d6b3750ffe235ec0fe4ccaa74328ba3c36529a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6000131
Reviewed-by: Rune Lillesveen futhark@chromium.org
Reviewed-by: Shunya Shishido sisidovski@chromium.org
Commit-Queue: Steinar H Gunderson sesse@chromium.org
Cr-Commit-Position: refs/heads/main@{#1380259}