Refcount SkStrikeCache Nodes

Change-Id: I3566345b8518b15603d6089626a7c3b493f8af17
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270438
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed