Remove PixelPackState from PackPixelsParams. Only one flag ("reverseRowOrder") from PixelPackState was being used, so instead of including the entire struct in PackPixelsParams, just include the one flag. BUG=angleproject:2718 Change-Id: I32e8b30383d198ecba9bf1719c32dda0938fc969 Reviewed-on: https://chromium-review.googlesource.com/1242210 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@google.com>