Rename some of GrThreadSafeCache's member variables

Cached vertex blobs are coming so the old 'view'-based names weren't helpful.

Bug: 1108408
Change-Id: Icf09182c8b71b511dad36e006e0f2129ee56635f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/328557
Reviewed-by: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
2 files changed