Update comment on isNumericalTransferFn to clarify that fn is always set
Update comment on isNumericalTransferFn to clarify that fn is always set

Change-Id: I7902e4355999f31bf92aa8294a2c1a32840249c2
Bug: chromium:960620
Change-Id: I7902e4355999f31bf92aa8294a2c1a32840249c2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/252479
Reviewed-by: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>
Reviewed-by: Mike Reed <f5cabf8735907151a446812c9875d6c0c712d847@google.com>
Commit-Queue: Brian Osman <794c0b5534edf5601d88e1d41975d0262da12894@google.com>

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