Remove unused fields from GrTextBlobKey

Change-Id: Ibb42f943ffbed16867d714e9a1eee35d3f422b2a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259282
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Herb Derby <herb@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
4 files changed