Updating the API description for Flutter

bug: skia:12850
Change-Id: I78148b2d99701a9127c377ddf709c89a885fcfc2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/502312
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Julia Lavrova <jlavrova@google.com>
1 file changed