Use Options object passed to startScanlineDecode

This->options() has not been updated to include the latest settings.

Originally brought up in crrev.com/1997703003, which has been reverted.
This is not really related to that change anyway, so separating it out.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2046493004

Review-Url: https://codereview.chromium.org/2046493004
1 file changed