The first bytes of the data always refer to the pixel accessed by texture coord (0, 0).
Change-Id: I708702d90f35b3bc896a48c3c3fd6a0be73f505a
Reviewed-on: https://skia-review.googlesource.com/112261
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
