Remove overly verbose Usage enum from FilterResult

Bug: skia:9282
Change-Id: I04afd352ad8c0c167993f29f4293d857f5af7170
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445619
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
7 files changed