Intersect SkPictureImageFilter bounds against clip bounds.

Intersect SkPictureImageFilter bounds against clip bounds
to avoid unnecessary processing. This is how the other
filters work (via applyCropRect()), but SkPictureImageFilter
maintains its own crop.

BUG=skia:
R=bsalomon@google.com

Author: senorblanco@chromium.org

Review URL: https://codereview.chromium.org/428263003
2 files changed