Remove StrikeRef

Change-Id: I3f16990da70c293a0d94d2cfb65163c7dfde06dd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/568799
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed