Make SkComposeImageFilter::onFilterImage filter the bounds given to the inner filter.

Previously, the bounds requested by the caller would be passed to both the
inner and outer filter, but since the outer filter may move pixels, this is not
necessarily sufficient to supply the pixels required by the outer filter to fill
the bounds.

Unit test included.

GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1813373002

Review URL: https://codereview.chromium.org/1813373002
2 files changed