Remove unused fields from SkScalerContextProxy

Change-Id: Ie6740ccb3302895dc9560e9a9278ab68dd64012b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/269903
Auto-Submit: Herb Derby <herb@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
3 files changed