remove filterSpan from SkColorFilter

Bug: skia:
Change-Id: Ie8a31ea8131c08d251a825622484342e3e174474
Reviewed-on: https://skia-review.googlesource.com/21207
Commit-Queue: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
18 files changed