Remove SkClampRange (unused)

Bug: skia:
Change-Id: I57fbdd39079a92e803902524a7950dd5f571639c
Reviewed-on: https://skia-review.googlesource.com/84961
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>
5 files changed