hide setImageFilter(ptr)

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4184

Change-Id: Iad792cfdf54087ad4c424fd268559c162a9a5f5c
Reviewed-on: https://skia-review.googlesource.com/4184
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
16 files changed