commit aef247af0a909f94cf9478c586cc64fabf333355
author scroggo <scroggo@chromium.org> Wed Oct 19 12:56:46 2016 -0700
committer Commit bot <commit-bot@chromium.org> Wed Oct 19 12:56:46 2016 -0700
tree 7132a4df4e1be903c3d50db537fc75255767a4b0
parent d6a1defd1f96c5cb7e82cad75edfa57c5f625fa1

Subtract start_coord instead of adding it

crrev.com/2420843003 (DIFFERENT ISSUE) introduced some changes in
sampled images. (I already corrected the problem for interlaced PNGs
in crrev.com/2424353003.)

When deciding whether a row is needed, we need to subtract the starting
coordinate, similar to how we subtracted fFirstRow in SkPngCodec.

This should "fix" the remaining untriaged images in Gold (i.e. we will
go back to producing the original image).
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2440563002

Review-Url: https://chromiumcodereview.appspot.com/2440563002