Ported chromium's curve fit code to C

Bug: skia:
Change-Id: I85a99651dfd0b9c0ccff4ba44db7640f1d527fb5
Reviewed-on: https://skia-review.googlesource.com/96866
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
9 files changed