Allow vertex data to be stored in the thread safe cache

Bug: 1108408
Change-Id: I4d51b9c837fad435c7a3e6823390b519b785631b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/329363
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed