davidmz/apng-chrome — pull request #20 by anall (2013-07-25 21:22:26+00:00)
Title: Fix hang in the case of a corrupted PNG chunk length

If a PNG chunk has an invalid length, this can get into an endless loop and cause the tab to hang.

Verify that:
* The length is not negative ( Shouldn't be possible per PNG spec, but happens due to treating the length as signed )
* The offset never goes backwards.