merge_pr_53270

Use TreeCountingChecker in font-style interpolations

Invalidate percentage interpolation for tree counting function changes
on DOM mutations.

Bug: 415626999
Change-Id: Ic8f51bdd910558dc68a34f49f8286d4ccbbf6caa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6652174
Reviewed-by: Rune Lillesveen futhark@chromium.org
Commit-Queue: Daniil Sakhapov sakhapov@chromium.org
Cr-Commit-Position: refs/heads/main@{#1476037}