rm unused fields
rm unused fields

Change-Id: I70c7c4769e0a8d95b590a85fab34529041f8af8a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/220841
Reviewed-by: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

HalCanary/skia-hc,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,google/skia,aosp-mirror/platform_external_skia,google/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,google/skia,google/skia