properly account for GrTextBlob arena size

The code was not accounting for the GrGlyphVector data properly. Add
that back in. Make a type AllSubRuns that accounts for the max size
of all the SubRuns.

Change-Id: I9ce702d24bc4f9efbfcdb4a0f14494f53d1b701c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/305568
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Herb Derby <herb@google.com>
2 files changed