Bodymovin uses tt: [1-4] to encode a layer track matte type, and skips
the property when a track matte is not present.
Flow OTOH uses explicit tt: 0 to signal the absence of a track matte.
Update the parser to not error out on tt: 0.
Change-Id: I2d456ac3479e356ba1fc5320589848f8872775e6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/445957
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
38ecac7895