need to apply CTM to clip rect in arithmetic imagefilter

BUG=skia:5800

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2708

NOTRY=True
upload steps are failing, but the tests themselves passed

Change-Id: I0210d0095b4ffdd376f18fad895655d39714bf38
Reviewed-on: https://skia-review.googlesource.com/2708
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
1 file changed