Remove 'f' prefix on SkRuntimeEffect::Varying struct

Change-Id: I10184e60617f65a513980e5389f226f2ebe3eb46
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/365656
Reviewed-by: John Stiles <johnstiles@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
3 files changed