# note: An ANMF chunk holding its header and nothing else, followed by a
#   real frame.
# expect: reject
# anim: ok
# info: reject
# exercises: A frame with no image is dropped rather than refused, and
#   quietly. StoreFrame() is handed a payload size of zero, reads the chunk
#   header belonging to the next frame, rewinds and returns having stored
#   nothing; the frame record it was filling still has the frame_num zero
#   WebPSafeCalloc() left, so the "frame->frame_num > 0" test in
#   ParseAnimationFrame() fails and it is freed. One frame comes out of a
#   file that declares two. webpinfo refuses the same file, though not for
#   that reason: it requires an ANMF to be strictly longer than its own
#   header, so it stops at "Truncated data detected when parsing ANMF
#   chunk" before it can notice there is no image.
frame
frame_duration 100
chunks
lossless
width 16
height 16
argb 0xff800000 x256
frame
frame_duration 100
lossless
width 16
height 16
argb 0xff008000 x256