Merge to XFA: Fix PNG decoding divide by zero error due to zero row count.

BUG=537790
TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1379243002 .

(cherry picked from commit 095a83c59120c108d9ac6f0ab71fd3faa5eea810)

Review URL: https://codereview.chromium.org/1380563003 .
1 file changed