benchmark for text vertex fill

Change-Id: If293360e2473be6d316cbfeccf8ec3ebeba2df1d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/309779
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed